Eating too much can lead to greater fat deposits, including around the belly, Hultin explained, so it's essential to follow a diet with appropriate calories for your needs. "Caloric needs are based on numerous factors, but the most important ones for a healthy individual include gender, age, weight, height, and activity level," added Stephanie Ferrari, a registered dietitian with Fresh Communications.
In order to determine how many calories you need, meet with a registered dietitian who can assess your lifestyle, goals, and health history to make recommendations (but this formula will give you an idea). Once you have a daily calorie amount in mind, measuring and weighing your food and tracking calories in an app such as MyFitnessPal can help you stay within your range. Keep in mind that even if you're eating healthy foods, the calories can quickly add up (we're looking at you, 800-calorie smoothie!).
Make sure you eat enough to keep your body and brain functioning properly, explained ACSM-certified personal trainer and registered dietitian Jim White, owner of Jim White Fitness and Nutrition Studios, because severely restricting calories can actually slow down your metabolism. Never dip below 1,200 calories, especially if you're also working out. For reference, the USDA dietary guidelines recommend adult women consume 1,600 to 2,400 calories a day, but that number will vary based on your age, height, weight, and activity level.