Overview Your body needs food for energy and strength. When you don't eat, your body relies on stored fat for energy and the nutrients it needs. This might sound like a good thing if you are trying to lose weight. But if you go too long without food or do it on a regular basis, your body begins to break down muscle for energy.Skipping Breakfast When you skip breakfast---the most important meal of the day---you're missing out on calories and nutrients that your body needs to get you through the first part of your day. Normally your body burns calories as energy, but when it doesn't get those calories, it begins to burn stored fat. A healthy lifestyle includes eating breakfast so that your body has the energy it needs to make it until lunchtime. Skipping breakfast can make you overeat by the time lunch rolls around because your body becomes so hungry.Skipping Lunch If you skipped breakfast, chances are you are very hungry by lunch. Skipping a second meal of the day leaves your body without the fuel it needs. You may feel warning signs that you need food: Headache, nausea, lightheadedness and feeling weak and sluggish are just a few side effects that you might feel from not eating all day.What Else Happens? Skipping breakfast and lunch can cause you to overeat at dinner because you are so hungry. Skipping meals on a regular basis causes your body to mimic starvation mode, which means you use fat for fuel. After a period of time, your body begins to break down muscle to use as energy. In addition, not eating slows your metabolism, which can make it even harder to lose weight.Dieting Tips Skipping meals to lose weight can be counterproductive. Instead, eat fewer calories at every meal and increase your physical activity. If you create a 500 calorie deficit each day, by a combination of eating fewer calories and burning off more calories with exercise, you can lose up to 1 lb a week.