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How Not to Diet: The Groundbreaking Science of Healthy, Permanent Weight Loss

by Michael Greger, M.D., FACLM

After reading this book in February of 2020, I wrote,


"Without good health, other things don't matter. A clear and compelling guide to a life of vitality..." 


Actually this is what I wrote about the book "How Not to Die" by the same author. But it applies double for this book.

The following 20 pages (as counted in 12-point type in Microsoft Word) are the clippings I took of all the major actionable information from Dr. Greger’s 570-page book (not counting the citations and index). I read this book twice to make sure I absorbed all the important points. You will notice many 3-4 digit numbers scattered throughout the extracted text below. In the Kindle version of the book, these numbers will link you to the citations that support his assertions. The book has about 5000 citations.


Although the focus of the book is creating and maintaining a healthy weight, more fundamentally and importantly, the book is about eating for vibrant health.

See all my book recommendations.  

Here are the selections I made:

I’m not interested in offering dueling anecdotes, nor am I interested in dietary dogma, beliefs, or opinions. What I am interested in is the science. When it comes to making life-and-death decisions that concern something as important as your own health and that of your family, as far as I’m concerned, there’s only one question: What does the best available balance of evidence say right now? That’s what I’ve tried to encapsulate in this book.


In the References section, I’ve included a website address and a QR code for the full list of the nearly five thousand citations referenced throughout this book.


A BMI between 18.5 and 24.9 is considered “ideal weight.”


Calculating your BMI is relatively easy: You can visit one of the scores of online BMI calculators, or you can grab a calculator and calculate it on your own. To do so, multiply your weight in pounds by 703. Then divide that twice by your height in inches. For example, if you weigh 200 pounds and are 71 inches tall (five foot eleven), that would be (200 × 703) ÷ 71 ÷ 71 = 27.9, a BMI indicating that you would be, unfortunately, significantly overweight.


The largest studies in the United States 394 [in the original Kindle book, numbers like this link to citations] and around the world395 found that having a normal body mass index, a BMI of 20–25, is associated with the longest life span.


Putting together all the best available studies with the longest follow-up, that can be narrowed down even further to a BMI of 20–22.


So even within a “normal” BMI, the risk of developing chronic diseases, such as type 2 diabetes, heart disease, and several types of cancer, starts to rise toward the upper end, starting as low as a BMI of 21. BMIs of 18.5 and 24.5 are both considered within the normal range, but a BMI of 24.5 may be associated with twice the heart disease risk compared to 18.5.397 The ideal BMI appears to be between 20 and 22, confirmed in a study of an “unusually slim cohort” from the Oxford Vegetarian Study.398


What’s the healthy waistline cutoff? 499 Increased risk of metabolic complications starts at an abdominal circumference of 31.5 inches in women and 37 inches in most men, but closer to 35.5 inches for Chinese, Japanese, and South Asian men.


the halfway point between the top of the hip bones and bottom of the rib cage appears to be the most effective at tracking changes in visceral fat over time.505


Unlike waist circumference, body mass index has the advantage of taking height into account. Waist-to-height ratio may offer the best of both worlds, and the cutoff value is the simplest to remember: Keep your waist less than half your height.506 The goal for adults and children six years or older is to get a waist-to-height ratio under 0.5.507


I’m such a stickler for veracity that I hired nine fact-checkers to go through every citation of the How Not to Die manuscript, and I committed to the same rigor with this book.


decided upon a more timeless, proactive approach: build an optimal weight-loss diet from the ground up. Based on the most compelling evidence my research team and I could find, I sought to generate a list of dietary attributes and components most effectual for weight loss. The best ingredients, if you will.



Take Off Pounds Sensibly (TOPS) is a nonprofit, peer-led weight-loss program that has been publishing its results for more than fifty years.923 Not having to siphon off money for shareholders, TOPS is five times cheaper than Weight Watchers and may be fifty times less expensive than other leading programs such as Nutrisystem or Jenny


As a physician, my priority is getting (and keeping) people healthy, but when people are surveyed about their motivation for dieting, disturbingly, “health” may come in last.927 Dieters want results—they want weight to come off.


One of the most important medical discoveries in recent years was the realization that inflammation appears to play a role in many of our chronic diseases, including at least eight of our top ten leading causes of death.


C-reactive protein levels in the blood are ideally under 1 mg/L,


Now that we have highly sensitive C-reactive protein blood tests that can measure levels to a fraction of a point, the medical community has realized that walking around with baseline levels of even just 2 or 3 mg/L appears to set us up for increased risk of catastrophes like heart attacks and strokes.933 Having a C-reactive protein level under 1 mg/L denotes low risk, yet the levels of most middle-aged Americans exceed this,934 suggesting most suffer from chronic inflammation. This


Broadly speaking, components of processed foods and animal products, such as saturated fat, trans fat, and cholesterol, were found to be pro-inflammatory, while constituents of whole plant foods, such as fiber and phytonutrients, were strongly anti-inflammatory.938 No surprise, then, that the Standard American Diet rates as pro-inflammatory and has the elevated disease rates to show for it. Higher Dietary Inflammatory Index scores are linked to a higher risk of cardiovascular disease939 and lower kidney,940 lung,941 and liver function.942 Those eating diets rated as more inflammatory also experienced faster cellular aging.943,944 In the elderly, pro-inflammatory diets are associated with impaired memory945 and increased frailty.946 Inflammatory diets are also associated with worse mental health, including higher rates of depression, anxiety, and impaired well-being.947 Additionally, eating more pro-inflammatory foods has been tied to higher prostate cancer risk in men948,949,950 and higher risks of breast cancer,951,952 endometrial cancer,953 ovarian cancer,954 and miscarriages in women. Higher Dietary Inflammatory Index scores are also associated with more risk of esophageal,955 stomach,956 liver,957 pancreatic,958 colorectal,959 kidney,960 and bladder961 cancers, as well as non-Hodgkin lymphoma.962 Overall, eating a more inflammatory diet was associated with 75 percent increased odds of having cancer and 67 percent increased risk of dying from cancer.963 Not surprisingly, those eating more anti-inflammatory diets appear to live longer lives.964,965,966,967 But how does the Dietary Inflammatory Index impact body weight? Obesity and Inflammation:


In the Dietary Inflammatory Index, the single most anti-inflammatory food is the spice turmeric, followed by ginger and garlic, and the most anti-inflammatory beverage is green or black tea. The two most anti-inflammatory food components are fiber and flavones.1021 Dietary fiber is found in all whole plant foods, but it is most concentrated in legumes, such as beans, split peas, chickpeas, and lentils.1022 Flavones are plant compounds concentrated in herbs, vegetables, and fruits,


and the leading sources in the U.S. diet are parsley, bell peppers, celery, apples, and oranges.1024 The most flavone-filled beverage is chamomile tea.


The most pro-inflammatory food components are saturated fat and trans fat. Essentially, the top five sources of saturated fat in the United States are cheese, desserts like cake and ice cream, chicken, pork, and then burgers.


The additional consumption of fourteen grams of fiber a day led to an average weight loss of 1.9 kilograms over 3.8 months.


Those on a Standard American Diet lose about 5 percent of the calories they eat in their waste,1198 but a higher-fiber diet can double that.


Fewer than 3 percent of Americans reach even the recommended minimum daily adequate intake of fiber.


Nearly everyone is suffering from a fiber-deficient diet, and that’s just based on the wimpy federal recommendations of fourteen grams per thousand calories, which comes out to be about twenty-five grams per day for women and thirty-eight daily grams for men.1273 That’s a far cry from the hundred grams our bodies were designed to get,1274 based on the diets of modern-day, isolated, hunter-gatherer tribes


Ninety-six percent of Americans don’t eat the minimum recommended daily amount of beans, 96 percent don’t eat the measly minimum for greens, and 99 percent don’t get enough whole grains.1285 Nearly the entire U.S. population fails to eat enough whole plant foods—the only place fiber is naturally found in abundance.


For millions of years, we may have evolved getting approximately 10 percent of our calories from fat.


The flesh of some wild game, like moose and elk, is less than 2 percent fat by weight and less than 15 percent calories from fat.


It’s been argued that for about 99.8 percent of our time on Earth, it was virtually impossible for us to regularly consume more than 15 percent of calories as fat.


At rest, we burn about one calorie a minute, which is comparable to the heat produced by a seventy-five-watt light bulb.


To store one hundred calories of dietary fat as body fat, it only takes three calories of energy, but converting one hundred calories of dietary carbs into fat for storage takes twenty-three calories.


The study found that 90 percent of the subjects inexplicably ramped up their exercise when they were unwittingly eating the low-saturated-fat diet, increasing their activity levels 12–15 percent on average. The researchers concluded that a high intake of saturated fat “might dampen motivation for physical activity.”


As I noted in the Causes section, more than 90 percent of adults and greater than two-thirds of the children in the United States are estimated to be “overfat”—that is, having excess body fat sufficient to impair health. This can occur even in people of normal weight (often due to excess abdominal fat).


At the time of the American Revolution, we consumed about an estimated four pounds of sugar per person per year.1575 Now, we may each average more than fifty pounds annually.1576 That’s the equivalent of about seventeen teaspoons of added sugars every day.


Note that none of these recommendations to cut down on added sugars applies to fruit. As you’ll read in the Rich in Fruits and Vegetables section, fruit can actually facilitate weight loss. If you randomize people to a diet low in all sugars, even the naturally occurring sugars in fruit, they do worse than those randomized to just cut down added sugars. Those who retained fruit in their diets lost nearly 50 percent more weight.


As I detail in the conclusion of How Not to Die, you can actually change your taste buds and end up with the best of both worlds: tastes great and more filling.


A single stomach full of strawberry ice cream, about two pints, could max out our caloric intake for an entire day.1698 What if you wanted to get those same two thousand or so calories from strawberries themselves? You’d have to eat forty-four cups of berries.1699 That’s eleven stomach fulls. As delicious as strawberries are, I don’t think I could fill my stomach to bursting eleven times in a day. Some foods are just impossible to overeat. They are so low in calorie density that you just couldn’t physically eat a big enough quantity to maintain your weight.


Zucchini is even less calorie dense than broccoli. You could eat 100 cups of sliced zucchini a day and still lose weight.1700 The calories in cucumbers are so dilute you’d have to eat more than 150 cups a day to gain weight1701 and more than 250 cups of chopped kale.


On average, those who eat low-energy-density diets consume hundreds of fewer calories, yet they eat significantly more food, about three-quarters of a pound more a day.


Fast food averages about 1,200 calories per pound,1709 whereas traditional African diets, which more closely represent the likely diet of our ancient ancestors, average fewer than 500 calories per pound.


How much food does it take to reach 2,000 calories at different caloric densities? As you can see in the graph below, you would need to eat eight pounds of food a day on a low-calorie-density diet of 250 calories per pound, whereas on a high-calorie-density diet, you’d have to restrict yourself to eating four times less food.


As a high-calorie-density food, the admonition to “eat sparingly” still applies, but that’s all one may need. While the optimum benefits of fruits and vegetables may require cups a day, nuts appear so potent that the mortality benefits may be had for mere ounces a week. FOOD


They aren’t smaller in general, though: Vegetarian boys and girls measure up to be about an inch taller than their “omnivorous classmates.”1798 They just aren’t as wide.



Where does TMAO come from? Just as short-chain fatty acids are produced by good bacteria in our gut when we eat fiber, TMAO originates from bad bacteria in our gut when we eat lots of choline (concentrated in eggs, but also lecithin supplements) or carnitine (concentrated in meat, but also some energy drinks).


Take chicken, for example. In 1896, the USDA determined chicken was about 23 percent protein and less than 2 percent fat by weight,1857 which is even leaner than some wild game like venison.1858 Today, with ten times the fat, chicken has 1,000 percent more fat than it did just over a century ago.1859 These days, more than 70 percent of the calories in chicken may come from fat.


To remove refined grains from your diet is to remove America’s number one source of calories. Switching to whole grains may help reduce body fat, but there’s an even better swap. See the Wall Off Your Calories section for taking your grain game up a notch and graduate from mere whole grains to intact whole grains, such as oat groats (also known as hull-less or hulled oats).


For most of human existence, we were only getting the pinch of salt a day naturally found in whole foods.1902 Now, thanks mostly to processed foods, we’re exposed to ten times more than our bodies were meant to handle.


The recommended dietary allowance for protein is about 50 grams a day (46 for women, 56 for men).


Traditional societies tend to have more diverse gut flora in general, and the key is thought to be their extraordinary fiber intakes, which can reach 120 grams a day,2104 nearly eight times the American average.


I mentioned earlier in which people lost weight after adding three apples or pears to their daily diets.2223 Certain other fruits were not as successful, though. Adding three grapefruit halves, around three kiwifruits, or half a mango a day didn’t result in significant weight loss (although it didn’t result in weight gain either).


In the Harvard cohorts, the categories of berries and apples/pears appeared to stand out on the fruit side in terms of foods associated with the most weight loss, and cauliflower and tofu/soy did so on the vegetable side.


One such study tried giving people with metabolic syndrome placebo or actual garlic tablets adding up to a half teaspoon of garlic powder a day. And it worked, resulting in a drop in both weight and waistlines within six weeks.2285 A half teaspoon of garlic powder costs less than four cents. What about trying garlic supplements, like the fancy aged garlic extract ones you may have seen advertised. No weight-loss benefits were found.2286


In the Harvard studies, the food category most associated with weight loss over time was soy food products, with nearly ten times the weight reduction associated with vegetable consumption.2313 But how many people are eating bacon double-cheese tofu burgers? Indeed, bean consumption is associated with less saturated fat and cholesterol intake,2314 so it may just be a marker for a healthier diet in general. Nevertheless, the Harvard studies controlled for a whole array of dietary and lifestyle factors yet still found a significant link between beans and better health.


What do you think happened when people were given a cup of chickpeas or the same number of calories of white bread and butter? Those who had eaten the chickpeas ate nearly two hundred fewer calories of a meal served a few hours later.2323 Navy beans may work even better than chickpeas, and lentils best of all.2324 How do legumes fare compared to something a little more substantial than Wonder Bread, though?


Researchers compared patties made with fava beans and split peas to protein-matched patties made out of meat. The title of the study gives it away: “Meals Based on Vegetable Protein Sources (Beans and Peas) Are More Satiating Than Meals Based on Animal Protein Sources (Veal and Pork).” Even lower-protein patties in which most of the mashed beans and peas were replaced with potato held their own against the meat.


Legumes have been found to be perhaps “the most important dietary predictor of survival in older people” around the world.


But feed people four servings a week of beans, split peas, chickpeas, and lentils, and you can get a whopping 40 percent drop in C-reactive protein,2368 a leading indicator of systemic inflammation. More beans equals less inflammation. Greater consumption

Split red or orange lentils are even easier. They’re ready in five minutes, quicker than boiling pasta.2372 Once they’ve softened, rinse them to cool, then mix with herbs and lemon juice for a basic legume salad. Another favorite of mine is to cook lentils a little longer so they thicken into almost a purée before adding spices like curry, turmeric, cumin, and garam masala for a thick, savory, and healthy Indian-inspired sauce.


Anyone can lose weight eating less food. Anyone can be starved thin. Starvation diets are rarely sustainable, though, since hunger pangs drive us to eat. We feel unsatisfied on low-calorie diets. Unsatiated. We do have some level of voluntary control, but our deep-seated instinctual drives may win out in the end. For


The four largest calorie contributors in the American diet are (1) refined grains, (2) added fats, (3) meat, and (4) added sugars.


Vegetarians and vegans are recommended to take supplements containing at least 50 mcg of cyanocobalamin (the most stable form2452) a day or at least 2,000 mcg once a week2453 (or brush twice daily with a B12-fortified toothpaste


As I explored in How Not to Die, these are the very same foods that in some cases may help prevent each of our top fifteen killers: (1) heart disease, (2) lung diseases, (3) iatrogenic (“death by doctor”) causes, (4) brain diseases, (5) digestive cancers, (6) infections, (7) diabetes, (8) high blood pressure, (9) liver diseases, (10) blood cancers, (11) kidney disease, (12) breast cancer, (13) suicidal depression, (14) prostate cancer, and (15) Parkinson’s disease.


There was a crossover study in which women were instructed to eat plant-based foods for a few months to see how it would affect their menstrual cycles. But then they were to switch back to their baseline diets to note the contrast, a so-called A-B-A study design where you reverse the experimental variable. The problem is that some participants felt so good eating healthfully—they were losing weight without any calorie counting or portion control, they had more energy, their periods got better, and they experienced better digestion and better sleep—that some refused to go back to their regular diets, which kind of messes up the study.2462


A key difference between plant-based nutrition and more traditional approaches to weight loss is that people are encouraged to eat ad libitum, which is, as I’ve noted, Latin for at one’s pleasure. In other words, people on a healthy enough plant-based diet can eat as much as they want.


In the ninety-thousand-person study, the average BMI of nonvegetarians was 28.8, bordering on obesity.2467 Semi-vegetarians or flexitarians, those who ate meat a few times a month but not every week, were at a BMI of 27.3. Those who ate no meat except fish came in at 26.3, and vegetarians were at 25.7. Vegetarian diet may seem a contradiction in terms, since how many vegetarians are on diets? But in the United States, even the average vegetarian is overweight. Only those eating purely plant-based diets were, on average, at an ideal weight with an average BMI of 23.6.


CHIP doesn’t provide meals—just advice and encouragement, empowering people with knowledge.2505 Within a month on the program, blood sugars, cholesterol, and blood pressures dropped enough for many participants to drop their antidiabetic, cholesterol-lowering, and blood pressure–lowering medications. Better numbers on fewer drugs, along with an average six-pound weight loss.


CHIP’s name was changed from the Coronary Health Improvement Project to the Complete Health Improvement Program.


A whole food, plant-based diet achieved the greatest weight loss ever recorded at six and twelve months compared to any other such intervention published in the medical literature.2527 The record-breaking study can be read in full for free at


Millions of years before we learned how to sharpen spears, mill grains, or boil sugarcane, our entire physiology is presumed to have evolved in the context of eating what the rest of our great ape cousins eat—leaves, stems, and shoots (in other words, vegetables), fruits, seeds, and nuts.


So for the first 90 percent of our hominoid existence, our bodies evolved on mostly plants.


The Trevose Behavior Modification Program.2545 Named after a town in Pennsylvania, the program has been running all-volunteer, self-help support groups since 1970, offering lifetime treatment at no cost. The most demonstrably successful weight-loss program in history is free? Why haven’t more people heard about it? Probably because it is free and doesn’t have a massive promotional budget like billion-dollar corporation Weight Watchers, which spends hundreds of millions on advertising every year.2546 After


One study found that twice daily—upon waking and again right before bed—appeared superior to once a day (about six pounds versus two pounds of weight loss over twelve weeks).2578


Was the weight loss simply statistically significant or actually significant? That’s for you to decide. During the three-month trial, compared to the placebo group, the group taking one daily tablespoon of vinegar steadily lost about a pound a month and the group taking two daily tablespoons were down a total of about five pounds. Five pounds may not sound like a lot, but that weight loss was achieved for just pennies a day without removing anything from their diets.


In a study refreshingly not funded by a vinegar company, two daily tablespoons of apple cider vinegar mixed into a drink reduced fasting blood sugars in prediabetics an average of sixteen points within one week, which is better than what you’d tend to see with antidiabetic drugs like Glucophage or Avandia.2650 The vinegar was found to be safer, cheaper, and more effective. No wonder vinegar has been used medicinally since antiquity.


I’d recommend sticking with more common culinary-type doses, like two tablespoons a day, which is considered safe.


Obese individuals randomized to just about four teaspoons of yacon syrup a day for 120 days lost nearly four inches off their waists and more than thirty pounds, whereas those on the placebo syrup gained weight.2674


To amp AMPK, I recommend trying two teaspoons of vinegar with each meal. You might be thinking, Wait—vinegar for breakfast? Those aghast at the thought of drizzling vinegar on their oatmeal may have never heard of chocolate vinegar, strawberry vinegar, or any of the dozens of other exotic flavors out there.


Overweight women were randomized to eat calorie-restricted weight-loss diets with or without a teaspoon of added cumin a day (half a teaspoon at both lunch and dinner). Over the three-month study, those in the cumin group lost about four more pounds and nearly an extra inch off their waists, in addition to significantly dropping their triglycerides and cholesterol.2727 Since cumin can be purchased in bulk for less than a dollar an ounce, a teaspoon would cost less than ten cents a day.


A recent systematic review and meta-analysis of randomized, controlled weight-loss trials found that about a quarter teaspoon of black cumin powder every day appears to reduce body mass index within a span of a couple of months.


Even weight loss of just a few pounds is pretty remarkable given the tiny doses utilized, about 100 mg, which is equivalent to around an eighth of a teaspoon of the spice. The problem is that saffron is the most expensive spice in the world. It’s composed of delicate threads poking out of the saffron crocus. Each flower produces only a few threads, such that you need fifty thousand flowers—enough flowers to fill a football field—to make a single pound of spice, so that pinch of saffron could cost up to a dollar a day.


A meal eaten at 7:00 a.m. can cause 37 percent lower blood sugars than an identical meal taken at 1:00 p.m.


So consuming more calories in the morning relative to the evening may actually have the triple benefit of more weight loss, better blood sugar control, and lower heart disease risk.


Night-shift workers have higher rates of obesity, as well as diabetes, cardiovascular disease, and cancer2884—graveyard shift indeed!


Regardless of the mechanism, bright morning daylight exposure could present a novel weight-loss strategy straight out of the clear blue sky.


Pistachios are not just the most melatonin-rich nut, they are off the charts as the most melatonin-rich food ever recorded.2957 To get a physiological dose of melatonin, all you have to eat is two. Two cups? Two handfuls? No, just two pistachios. Pistachio nuts were found to contain 0.2 mg of melatonin per gram.2958 It only takes 0.3 mg of melatonin to cause the normal daily spike our brains give us, so just two nuts would presumably do the trick.2959


Sleep during the night and be active during the day Sleep enough (seven to eight hours a night) Early to bed, early to rise Avoid bright light exposure at night Sleep in total darkness when possible Eat dinner at least two and a half hours before going to bed Avoid eating at night I


Their bodies didn’t seem to fully recognize the extra calories when they were in liquid form and, therefore, didn’t compensate by reducing their appetites for the rest of the day.


Those who chewed thirty-five times per bite ended up eating about a third of a cup less pasta than those who had only chewed ten times per bite.


People were given soup, but half were given small spoons and told to eat slowly, and the other half were given big spoons and told to eat quickly, and an amazing thing happened: The slow-eating group not only ended up feeling more satiated, but they did so after eating less soup.2977 They felt fuller eating less food.


As Harvard’s Healthy Weight Checklist puts it: “Slowing down at meals … can help avoid overeating by giving the brain time to tell the stomach when it’s had enough food.”


Preload studies, where people are fed a first course one, five, fifteen, twenty, thirty, or sixty minutes before the main meal, show that this fullness feedback loop may take about twenty minutes to fully tamp down our appetites.


In smoothie form, you can drink fruits and vegetables at about two cups a minute—ten times faster than it might take to eat fruits and vegetables in solid form.


study when chewing a bite thirty-five times was shown to beat out chewing only ten times and resulted in 12 percent fewer calories eaten at a meal.


If you ask people to double their baseline number of chews per bite, they end up eating about 15 percent less pizza, feeling just as full eating more than one hundred fewer calories.2996 Even just asking them to chew 50 percent more times than normal may cut their consumption by nearly 10 percent.2997


Experiments simultaneously varying bite size and oral exposure time with solid food found the same phenomenon: It’s better to nibble and savor than chomp and gulp.


demonstrated that regardless of how we boost the amount of time food is in our mouths, it can result in lower caloric intake.


When people were put on a diet packed with fruits, vegetables, whole grains, and beans and allowed to eat all they wanted, they ended up eating 48 percent fewer calories than they might have otherwise.


Part of that was due to the lower calorie density of the plant-heavy diet, but people also spent about 40 percent more time chewing, for seventeen minutes per meal compared to twelve minutes.


researchers recognized that nearly any diet can cause weight loss at least short term, but the ends don’t always justify the means. Their challenge was to design a “nutritionally sound” diet “conducive to a lifelong pattern of healthful eating.”3074 To that end, the diet encourages people to eat more high-bulk, calorie-dilute foods (vegetables, fruits, whole grains, and beans) and fewer energy-dense foods (meats, cheeses, sugars, and fats).


So choose foods that take longer to eat, and eat them in a way that prolongs the time they stay in your mouth. Think bulkier, harder, chewier foods, such as apples, carrots, or intact grains, eaten in smaller, thoroughly chewed bites. Snack on raw veggies, and fall in love with soup. If possible, extend meal duration so it lasts at least twenty minutes to allow your natural satiety signals to take full effect.


Try eating with chopsticks. Even in experienced hands, they tend to slow eating rate.


The Exercise “Myth” When trying to lose weight, which is more important: diet or exercise? A national survey found that a “vast majority” of Americans, seven out of ten, believe that food and beverage consumption and physical activity are equally important when it comes to weight loss. About two out of ten favored exercise, and only about one in ten chose diet.3080 The vast majority of Americans are wrong.


In contrast, even most “active” people exercise less than two hours a week, which may average out to fewer than one hundred calories burned off daily.


Though most people believe exercise is a “very effective” way to lose weight,3085 that has been referred to as a “myth” in the scientific literature.3086 In fact, it’s been labeled as one of the most common misconceptions in the field of obesity,


Can You Outrun a Bad Diet? Dozens of randomized controlled trials involving thousands of participants have been published on the effects of exercise on weight loss.3090 How did exercise fare? Surprisingly, physical activity was not found to be an effective strategy.3091 Think of it this way: A moderately obese person doing moderate-intensity physical activity, like biking or very brisk walking, would burn off approximately 350 calories an hour.3092 Most drinks, snacks, and other processed junk are consumed at a rate of about 70 calories a minute. Therefore, it only takes five minutes of snacking for someone to wipe out a whole hour of exercise.3093


When people are randomized into diet-and-exercise interventions versus diet alone, the diet-and-exercise groups do better, but the difference in weight loss only averages about two pounds.3095 The studies lasted between three and twelve months, and all that extra prescribed exercise seemed to translate into only a few pounds lost.


The longer-term trials performed even worse. In a meta-analysis of eighteen randomized controlled studies lasting a minimum of six months, the diet-plus-exercise group failed to beat out the diet-only group at all.


To walk off the calories found in a single pat of butter, we’d have to add an extra seven hundred yards to our stroll that evening. What about a Snickers bar? We’d need to jog a quarter mile for every single bite.


Studies show obese individuals tend to remain seated for about two and a half hours longer each day than the average, inactive yet lean, shoestring couch potato.3174 Normal-weight individuals just tend to get up and move around more.

Remarkably, those small moments of movement can add up to more than two thousand calories a week, which just so happens to be what those overfed study subjects started burning up and about what you’d get from the hour-a-day exercise recommended for weight loss.


The reason the Amish have some of the lowest rates of obesity is not a high prevalence of gym memberships. They walk an average of eighteen thousand steps a day just living their lives.


After twelve weeks, there was a greater reduction in waistlines and body-fat percentage in the hibiscus group compared to those who got placebo capsules,


I personally do mostly kale, collards, and arugula, which also happen to have the added benefit of being cruciferocious. And you can enjoy it with a cup of hibiscus tea for added zing.


Cold exposure is the most powerful known stimulus for BAT activation.3469 Just twenty minutes at cool temperatures can boost metabolism for hours.3470 The colder the better, but putting people in a room chilled down into the 50s Fahrenheit is “often not appreciated by [research] subjects.”3471 It’s not called a “thermal comfort zone” for nothing. Exposure


moving within the range of climate-controlled buildings from 75°F down to 66°F has been proven to boost BAT activation. This resulted in a 5 percent boost in metabolic rate, so about one hundred more calories burned every day or an annual calorie-deficit equivalent of approximately twenty days of fasting.3477 So just a slight thermostat shift to a cool-but-not-too-cold ambient temperature may have a significant effect.


Those randomized to even just thirty seconds a day of a cold-water blast ended up taking off fewer sick days from work.3484 Foods


Bottom line: Putting together all the randomized controlled trials of ginger powder, two to twelve weeks of a quarter teaspoon to one and a half teaspoons a day of ground ginger significantly decreased body weight for just pennies a day.


Interventional studies putting around three to six cups’ worth of daily green or oolong tea to the test showed an average metabolic boost of about one hundred calories a day, shaving off three butter pats’ worth of extra fat every day.


That is one reason most of the spotlight has been on green, white, and oolong teas, as they have about five times more EGCG than black tea.


Within eight weeks, those in the green tea group were down an average of ten pounds compared to about four pounds in the placebo group. Given the identical diets and no significant change in exercise, this suggests the primary green tea benefit is from burning more calories, which was confirmed by calorimetry. The green tea resulted in a significantly higher resting metabolic rate.


Researchers found the addition of milk “completely prevents the biological activity of tea.”


On average, every cup of coffee may cause you to end up burning seventeen extra calories.3717 Since a cup of black coffee only has about two calories,3718 that leaves a net deficit of fifteen calories per cup. But only a third of U.S. coffee consumers drink their coffee without cream or sugar.3719 While drinking coffee black could push your calorie ledger into the red, added creamer or caloric sweeteners could easily wipe out any benefit.3720 There are some Dunkin’ Donuts coffee drinks with more than a thousand


Note that to break a bad habit or create a new one, we have to select a new action (eat an apple) rather than just give up an existing behavior (don’t eat potato chips).3798 To activate the habit-forming mechanism, you likely need a new alternative response, rather than a nonresponse.


People seem to be better able to deal with coming up short on positive goals than negative ones. So framing your subgoals as things you want to accomplish, rather than avoid, can help you escape the fatalistic, black-and-white thinking that can subvert your longer-term goals.


The group of overweight nine- to twelve-year-olds randomized to the water intervention was told to increase their water intakes to the point their urine became straw-colored (pale yellow). Once again, not every kid complied, but those who did lost significantly more weight.3856 Inspired


Is there any danger in drinking too much water? Absolutely, yes. Even healthy kidneys can only handle about three cups of water an hour.


the single most pro-inflammatory food component is saturated fat. The single most anti-inflammatory food component? Fiber.3899 Since saturated fat is found mostly in meat, dairy, and junk food, whereas fiber is abundant in whole grains, beans, vegetables, and fruit,


A completely plant-based diet, however, can help drop C-reactive protein levels by 30–40 percent within just a few weeks in both adults3905 and children,


Goji berries, also known as wolfberries, have at least four times the antioxidant activity compared to other dried fruits like raisins or dried cranberries that you might sprinkle on your oatmeal or add to your trail mix.


Both were given identical instructions to follow a healthier diet, but one group was also given fourteen grams of dried goji berries a day, which is about two tablespoons.3923 Forty-five days later, the goji group appeared to cut two and a half inches off their waistlines


Give people about a quarter cup a day of tomato paste, and get an improvement in artery function within fifteen days, an effect attributed to both anti-inflammatory and antioxidant effects.


Women who were asked to eat a ripe tomato before lunch every day for one month dropped two pounds with improvements in blood sugars, cholesterol, and triglycerides.


A special type of fiber called beta-glucan in brewer’s, baker’s, and nutritional yeasts displays anti-inflammatory effects3956 sufficient to improve wound healing3957 and alleviate symptoms in ragweed sufferers.3958 Randomized, double-blind, placebo-controlled clinical trials of about two teaspoons of nutritional yeast’s worth of beta-glucans have resulted in about an inch off the waist within six weeks3959 or up to a five-pound weight benefit compared to controls in twelve weeks, along with an improvement in blood pressure.3960


and we know who shouldn’t be fasting in the first place4109 (such as those with advanced liver or kidney failure, porphyria, or uncontrolled hyperthyroidism, and women who are pregnant or breastfeeding).


A meta-analysis of four cohort studies following the diets, diseases, and deaths of more than a quarter million people found that those who eat lower-carb diets suffer a significantly higher risk of all-cause mortality, meaning they live, on average, significantly shorter lives.4188 The risk of cardiovascular disease specifically appears to depend on the source of fat. In a Harvard study of heart attack survivors, those who adhered more to a lower-carb diet based on animal sources of fat and protein had a 50 percent higher risk of dying from a heart attack or stroke, but no such association was found for lower-carb diets based on plant sources.4189 These studies were based on low-carb scoring systems, though, so they speak more to the risks of lower-carb eating rather than a truly low-carb ketogenic diet.


Any diabetic can maintain normal blood sugars eating a stick of butter; only a cured diabetic can maintain the same feat eating a banana. As I detailed in How Not to Die, diabetes truly can be reversed this way with a healthy enough diet, sometimes in a matter of weeks and even without weight loss.4205


The dropout rates in time-restricted feeding trials certainly appear lower than in more prolonged forms of intermittent fasting, suggesting they’re more easily tolerable,4320 but do they work? When people stopped eating between 7:00 p.m. and 6:00 a.m. for two weeks, they lost about a pound each week compared to no time restriction. Note that no additional instructions or recommendations were given on the amount or type of food consumed. There were no gadgets, calorie counting, or record keeping. They were just told to limit their food intakes to the hours of 6:00 a.m. through 7:00 p.m.


The next logical step was to try putting it to the test for months instead of just a couple of weeks. Obese men and women were asked to restrict eating to the eight-hour window between 10:00 a.m. and 6:00 p.m. Twelve weeks later, they had lost five pounds.


frontloading one’s calories earlier in the day with a prolonged nightly fast has been associated with significant weight loss over time, leading the researchers to conclude: “Eating breakfast and lunch 5–6 h[ours] apart and making the overnight fast last 18–19 h[ours] may be a useful practical [weight control] strategy.”


Ketogenic diets are also not recommended. When you think of the ideal attributes of a diet for weight control—safe, effective, protective, healthful, wholesome, sustainable, nutritionally complete, and life-extending—typical keto diets guarantee none of them.


The healthiest snacks are fresh fruits and vegetables, of course, but I also enjoy snacking on nori sheets, lentil sprouts, “air-fried” purple sweet potato fries, edamame, and seasoned air-popped popcorn.


The worst snacks, according to national snacking guidelines from around the world, are snacks that are sugary, fatty, or salty.


Try this at home: Measure your heart rate before and after drinking two cups of water. Within ten minutes of drinking the water, your heart rate should slow by about four beats per minute, and by fifteen minutes, you should be down six or seven beats.


Drinking two cups of water increased the metabolic rate of men and women by 30 percent. The increase started within ten minutes of water drinking and reached a maximum within an hour. In the ninety minutes after drinking a single tall glass of water, the subjects burned an extra twenty-four calories.4437 Simply drinking a tall glass of water four times throughout the day would wipe out nearly one hundred extra calories, more than the calories burned by taking weight-loss doses of the now-banned ephedrine three times a day.4438 Plain, cheap, safe, and legal tap water!


Fifty overweight women aged eighteen through twenty-three were asked to drink, over and above their regular water intakes, two cups of water three times a day a half hour before meals without otherwise changing their diets or physical activity. They lost an average of three pounds in eight weeks.


What if you give young adults two cups of water immediately before a meal? Do they then eat less? Indeed, they eat about 20 percent less, taking in more than one hundred fewer calories.


Preloading with vegetables can effectively subtract one hundred calories out of our diets. That’s how you can lose weight by eating more food.


We’ve learned from studies on preloading that eating about a cup of food before a meal decreases subsequent intake by about one hundred calories, so to get a “negative calorie” effect, the preload has to contain fewer than one hundred calories per cup.4556,4557 As you can see in the Calories per Cup chart in the Low in Calorie Density section, that would include most fresh fruits and vegetables.


By frontloading the most healthful foods first, when you’re hungriest, you may also eat more of them.4559 Those given a salad before a meal ate more salad than when it was competing for their attention during the meal.4560 So part of the magic of preloading may indeed lie in eating more low-calorie-density foods after


Give people a large apple to eat before that same pasta meal instead of the salad, and rather than consuming about two hundred fewer calories, they consumed more than three hundred fewer calories.4566 So how many calories does an apple have? It depends on when you eat it. Before a meal, it may effectively have negative two hundred calories!


Starting a meal with foods containing fewer than one hundred calories per cup can result in fewer overall calories consumed. This includes many fruits, vegetables, soups, salads, or simply a tall glass of water.


sleep deprivation tends to lead people to overeat by about 180–560 calories a day.


Overall, most sleep improvement interventions tend to show improved weight loss, giving a positive spin to the phrase You snooze, you lose.


Four Rules of Sleep Conditioning:4658 Go to bed only when you’re sleepy. Only use the bed for sleep (and sex). No reading, eating, or screen time. If you can’t fall asleep within fifteen to twenty minutes or so, get up, leave the bedroom, and don’t go back until you’re sleepy again. Repeat as necessary. Get up at the same time every morning no matter how little sleep you have had.


Four Rules of Sleep Hygiene:4660 Exercise regularly. Avoid caffeine, nicotine, and alcohol before bedtime. Make the bedroom dark, cool, comfortable, and quiet. Establish a relaxing bedtime routine.


However, it’s clear that hefty caffeine doses up to six hours before bedtime interfere with sleep. Late-afternoon alcohol consumption (six hours before bedtime) may also impair sleep.4665 Additionally, nicotine, whether from gum, pill, patch, vape, or cigarette, may have negative sleep effects4666—though active nicotine withdrawal may as well.


Under stress, we tend not only to eat more food but worse food, and we seem to deposit more fat in the worst place, in and around our abdominal organs.


The mindful eating approach, on the other hand, involved cognitive defusion. People are taught to defuse their thoughts as “merely thoughts” and place mental distance between themselves and their thoughts. A defusion response to the thought of needing chocolate would involve simply observing the thought (I notice I’m having the thought that I need to eat some chocolate) and thanking one’s mind for the thought (Thanks, mind).4782 A “mindbus” metaphor is used, in which people are taught to imagine themselves as the driver of a bus and their thoughts as mere passengers.4783 You visualize yourself taking control as you stop the bus and let off the negative passengers. Thanks for the feedback, folks, but this is my bus. 


Cognitive defusion was tested head-to-head against cognitive restructuring in the same chocolate experiment, and those who had gotten an hour of defusion instruction had three times greater odds of remaining “chocolate abstinent” in the face of a week of constant temptation.


This may help explain why sugary drinks have been blamed as perhaps the single largest driver of the obesity epidemic,4856 accounting for at least one-fifth of the weight gained between 1977 and 2007 in the United States.4857 By the year 2000, Americans were drinking an estimated 190 calories a day of sweetened beverages.4858


Comparing the absorption of fat from peanuts to the exact same number of peanuts ground into peanut butter, you flush more than twice the amount of fat down the toilet when you eat the peanuts themselves.


When you eat spaghetti, you get a gentle rise in blood sugars.4898 If you eat the same amount of wheat baked into bread form, however, you get a big spike in blood sugars.


Individuals were randomized into one of three breakfast conditions—oatmeal made from quick oats, the same number of calories of Frosted Flakes, or just plain water—and then the researchers measured how much the subjects ate for lunch three hours later. Unsurprisingly, those who had eaten the oatmeal felt significantly fuller and less hungry after a few hours and indeed went on to eat significantly less lunch. Overweight participants in the oatmeal group ate less than half as many calories at lunch, hundreds of fewer calories compared to the other groups. How did the cereal group fare? The breakfast cereal was so unsatiating that the Frosted Flakes group ate as much lunch as the breakfast-skipping water-only group.4902 It’s as if the cereal group hadn’t eaten any breakfast at all.


Yes, fiber supplements can help with constipation, but all the other purported benefits didn’t seem to materialize. Studies associating high fiber intake with lower risk of disease and death relate only to fiber from food intake rather than from fiber isolates or supplements.


That’s why the glycemic index of intact wheat kernels (wheatberries) or even cracked wheat (like bulgur found in tabbouleh) is down around 45, but whole-wheat bread is nearly as bad as white bread with both up about 70.


The glycemic index of pasta is in the moderate range, at 55, compared to the glycemic index of even whole-wheat bread, which may exceed 70.


As I mentioned in the Fat Blockers section, I defined my Green Light category in How Not to Die as foods of plant origin to which nothing bad has been added and from which nothing good has been taken away.


Former Harvard nutrition chair Walter Willett has argued that the term whole grain should probably be reserved for only whole intact grain kernels.4978 So eat the wholiest of grains: intact grains, also known as groats.


like to start my mornings with what I call my BROL bowl. BROL stands for barley, rye, oats, and lentils. Most people are only familiar with pearled barley, which is partially refined by having some of its bran polished off. You can buy barley groats, sold as hulled or hull-less barley. If your budget allows, go for purple barley, which naturally contains some of the antioxidant pigments found in berries as a bonus. Rye groats are typically sold as rye berries. Oat groats are just oat groats, though I’ve also seen the terms hull-less and hulled oats. And since I know I should probably check off a morning legume box on my Daily Dozen, I add black lentils, which are the most antioxidant-packed,4982 sold as beluga lentils due to their resemblance to expensive caviar.


At Each Meal Preload with Water Time your metabolism-boosting two cups of cool or cold unflavored water before each meal to also take advantage of its preload benefits.

Preload with “Negative Calorie” Foods As the first course, start each meal with an apple or a Green Light soup or salad containing fewer than one hundred calories per cup.

Incorporate Vinegar (2 tsp with each meal) Never drink vinegar straight. Instead, flavor meals or dress a side salad with any of the sweet and savory vinegars out there. If you want to drink it, make sure to mix it in a glass of water and, afterward, be sure to rinse your mouth out with water to protect your tooth enamel.

Enjoy Undistracted Meals Don’t eat while watching TV or playing on your phone. Give yourself a check for each meal you’re able to eat without distraction.

Follow the Twenty-Minute Rule Whether through increasing viscosity or the number of chews, or decreasing bite size and eating rate, dozens of studies have demonstrated that no matter how we boost the amount of time food is in our mouths, it can result in lower caloric intake. So extend meal duration to at least twenty minutes to allow your natural satiety signals to take full effect. How? By choosing foods that take longer to eat and eating them in a way that prolongs the time they stay in your mouth. Think bulkier, harder, chewier foods in smaller, well-chewed bites.


  • Every Day Take Your Daily Doses Black Cumin (Nigella sativa) (¼ tsp) As noted in the Appetite Suppression section, a systematic review and meta-analysis of randomized, controlled weight-loss trials found that about a quarter teaspoon of black cumin powder every day appears to reduce body mass index within a span of a couple of months. Note that black cumin is different from regular cumin, for which the dosing is different. (See below.)

  • Garlic Powder (¼ tsp) Randomized, double-blind, placebo-controlled studies have found that as little as a daily quarter teaspoon of garlic powder can reduce body fat at a cost of perhaps two cents a day.

  • Ground Ginger (1 tsp) or Cayenne Pepper (½ tsp) Randomized controlled trials have found that ¼ teaspoon to 1½ teaspoons a day of ground ginger significantly decreased body weight for just pennies a day. It can be as easy as stirring the ground spice into a cup of hot water. Note: Ginger may work better in the morning than evening. Chai tea is a tasty way to combine the green tea and ginger tweaks into a single beverage.

  • Alternately, for BAT activation, you can add one raw jalapeño pepper or a half teaspoon of red pepper powder (or, presumably, crushed red pepper flakes) into your daily diet. To help beat the heat, you can very thinly slice or finely chop the jalapeño to reduce its bite to little prickles, or mix the red pepper into soup or the whole-food vegetable smoothie I featured in one of my cooking videos on

  • Nutritional Yeast (2 tsp) Two teaspoons of baker’s, brewer’s, or nutritional yeast contains roughly the amount of beta 1,3/1,6 glucans found in randomized, double-blind, placebo-controlled clinical trials to facilitate weight loss.

  • Cumin (Cuminum cyminum) (½ tsp with lunch and dinner) Overweight women randomized to add a half teaspoon of cumin to their lunches and dinners beat out the control group by four more pounds and an extra inch off their waists. There is also evidence to support the use of the spice saffron, but a pinch a day would cost a dollar, whereas a teaspoon of cumin costs less than ten cents.

  • Green Tea (3 cups) Drink three cups a day between meals (waiting at least an hour after a meal so as to not interfere with iron absorption).

  • During meals, drink water, black coffee, or hibiscus tea mixed 6:1 with lemon verbena, but never exceed three cups of fluid an hour (important given my water preloading advice). Take advantage of the reinforcing effect of caffeine by drinking your green tea along with something healthy you wish you liked more, but don’t consume large amounts of caffeine within six hours of bedtime.

  • Taking your tea without sweetener is best, but if you typically sweeten your tea with honey or sugar, try yacon syrup instead. 

  • Stay Hydrated Check this box if your urine never appeared darker than a pale yellow all day. Note that if you’re eating riboflavin-fortified foods (such as nutritional yeast), then base this instead on getting nine cups of unsweetened beverages a day for women (which would be taken care of by the green tea and water preloading recommendations) or thirteen cups a day for men. If you have heart or kidney issues, don’t increase fluid intake at all without first talking with your physician.

  • Remember, diet soda may be calorie-free, but it’s not consequence-free, as we learned in the Low in Added Sugar section.

  • Deflour Your Diet Check this box every day your whole grain servings are in the form of intact grains. The powdering of even 100 percent whole grains robs our microbiomes of the starch that would otherwise be ferried down to our colons encapsulated in unbroken cell walls.

  • Front-Load Your Calories There are metabolic benefits to distributing more calories to earlier in the day, so make breakfast (ideally) or lunch your largest meal of the day in true king/prince/pauper style.

  • Time-Restrict Your Eating Confine eating to a daily window of time of your choosing under twelve hours in length that you can stick to consistently, seven days a week. Given the circadian benefits of reducing evening food intake, the window should end before 7:00 p.m.

  • Optimize Exercise Timing The Daily Dozen’s recommendation for optimum exercise duration for longevity is ninety minutes of moderately intense activity a day, which is also the optimum exercise duration for weight loss. Anytime is good, and the more the better, but there may be an advantage to exercising in a fasted state, at least six hours after your last meal. Typically, this would mean before breakfast, but if you timed it right, you could exercise midday before a late lunch or, if lunch is eaten early enough, before dinner. This is the timing for nondiabetics. Diabetics and prediabetics should instead start exercising thirty minutes after the start of a meal and ideally go for at least an hour to completely straddle the blood sugar peak. If you had to choose a single meal to exercise after, it would be dinner, due to the circadian rhythm of blood sugar control that wanes throughout the day. Ideally, though, breakfast would be the largest meal of the day, and you’d exercise after that—or, even better, after every meal.

  • Weigh Yourself Twice a Day Regular self-weighing is considered crucial for long-term weight control, but there is insufficient evidence to support a specific frequency of weighing. My recommendation is based on the one study that found that twice daily—upon waking and right before bed—appeared superior to once a day (about six versus two pounds of weight loss over twelve weeks).

  • Complete Your Implementation Intentions Every two months, create three new implementation intentions—“if X, then Y” plans to perform a particular behavior in a specific context—and check each one off as you complete them every day.

  • Every Night Fast After 7:00 p.m. Because of our circadian rhythms, food eaten at night is more fattening than the exact same food eaten earlier in the day, so fast every night for at least twelve hours starting before 7:00 p.m. The fewer calories after sundown, the better.

  • Get Sufficient Sleep Check this box if you got at least seven hours of sleep at your regular bedtime. –

  • Experiment with Mild Trendelenburg Try spending at least four hours a night lying with your body tilted head-down six degrees by elevating the posts at the foot of your bed by eight inches (or by nine inches if you have a California king). Be extremely careful when you get out of bed, as this causes orthostatic intolerance in most people, even if you’re young and healthy—meaning if you get up too fast, you can feel dizzy, faint, or light-headed and could fall and hurt yourself. So get up slowly. Drinking two cups of cold water thirty minutes before rising may also help prevent this potentially hazardous side effect. IMPORTANT: Do not try this at home at all if you have any heart or lung issues, acid reflux, or problems with your brain (like head trauma) or eyes (even a family history of glaucoma disqualifies you). Also do not try this until you ask your physician if they think it’s safe for you to sleep in mild Trendelenburg.


Tick All the Right Boxes Between the twenty-four checkboxes in the Daily Dozen and the thirty-seven new checkboxes in the Tweaks, you may feel a bit overwhelmed, but it’s easy to knock off a bunch at a time. For example, starting a meal with a tomato salad sprinkled with some black cumin, garlic powder, and balsamic vinegar hits five boxes right there, including the “Preload with ‘Negative Calorie’ Foods” tweak and the Daily Dozen box for “Other Vegetables.” And if that was one of your implementation intentions, make that six! Ten percent of your boxes nailed with a single appetizer. Of course, you don’t have to hit all the booster boxes every day. You don’t even have to hit any. A healthy diet, as encapsulated by the Daily Dozen, should be all you need to lose as much weight as you want, but the more of these extra tweaks you can hit, the more successful you may be. I’m working on an entire How Not to Diet Cookbook to try to fit as many of these combinations together into delicious recipes and hearty meal plans—but in the meanwhile, please feel free to download the free, updated Dr. Greger’s Daily Dozen app on your Android or iPhone. Start experimenting with a few of the Twenty-One Tweaks and see which ones work for you. My goal is to provide you with the broadest palette of tools to choose from. Remember, it’s not what you eat today that matters, or tomorrow, or next week, but rather what you eat over the next months, years, and decades, so you have to find lifestyle changes that fit into your lifestyle.

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