Intermittent fasting defines when to eat, not what or how much. You should still aim to eat your daily calories during your eating window and not have too much of a calorie deficit. If you're not eating enough, or you're cutting certain foods out like carbs, or you're only eating foods you think you're supposed to eat but hate (we're looking at you, celery juice!), then deprivation will drive you to overeat. Leslie said to focus on healthy, filling foods, and remember that it's OK to indulge and have fun foods, too!