"I never lose sight of the fact that just being is fun."
-Katharine Hepburn, actress (1907-2003)
When you join your Now in being present, your Now will often be happy and agreeable with whatever your Next is doing or wanting to do.
How often do you notice your thoughts? How many of them are about the past or the future? You will find that few of them are about what's present now.
It's a new habit to bring yourself to now: to take your focus off the past or the future. Use kickstarting a mental habit to install the mental habit of asking, "Am I present now?"
You can still engage in activities that your my-next is interested in (like exercising or eating healthfully). But what you'll often find is that any resistance that your my-now has your current activity ("i'm not really enjoying this exercise") will disappear when your bring your awareness to now.
One more specific physical way to assist in being present now is to slow down. Do things in a bit of "slow motion." This contributes to being now and enjoying now.
If it's problematic to bring yourself to now, resisted fear may be the issue. Take yourself through one of the following exercises to dissolve this fear: undoing fear, undoing worry, undoing stress, undoing procrastination, undoing guilt, undoing expectations.