Some people have experienced a “high” when they became involved in exercise. While the “high” is not wrong, it is not complete. And usually, obsessive, tedious exercise to become thin eventually wears thin if the exercise is self-focused rather than God-focused. Exercise, like food, must also be put in its place and not worshiped, but enjoyed.
The transfer to a heavenly focus from a focus on food, exercise, or anything else is much more delightful and fulfilling. It has so many rewards that you will never want to return to giving your heart to anything else!