1. You're not eating well. Eating less often does not make you lose weight. It will, probably for some time, but then you'd get overweight again and probably even worse. Imagine all that sacrifice with little to zero result. To get an idea why you need to eat enough and why you need to get rid of strict diets, see this article.
2. You eat the wrong foods. There are foods that worsen your metabolism. Some even destroy it. And foods that damage metabolism (tend to slow it down), like processed foods, have the most TV ads--even billboard and newspaper ads--telling you how they're supposed to be "fortified" with vitamins and minerals. Or probably you've been eating in fast food stores. Eat home-cooked meals so you can control your salt, fat and carb intake and make sure they have zero preservatives.
3. Your body is probably toxic. Even with the right healthy foods and workouts. you won't lose weight if you are toxic. How does your body become toxic? Simple--stress. Unhealthy stress daily will make everything you do to lose weight useless. Then add to that the junk foods and drinks you take also everyday (and are added expense). Start living a really happy life, with less worries, and eating natural healthy foods.
4. Your body tends to store more fat. Some people tend to store more fat in their bodies especially around their bellies. Why? It's mostly about slow metabolism. Sometimes it runs in the family. How do you program a faster metabolism? For starters, eat a healthy breakfast daily and keep physically active. Eat fresh fruits before meals. Eat less for supper--and then take a snack 30 minutes before you go to bed at night. Why? It boosts metabolism in the morning, says two studies done at the Florida State University mentioned in an article on Health.Com. Eat before-bedtime snack limited to 150 calories.
5. Carb intolerance. Examine yourself--if you see your belly and hips growing bigger each time you eat carbs, then eat less carbs. Don't get rid of it totally, though. You also need carbs to lose weight. The trick here is to lessen. Eating 5 small meals a day instead of 3 large ones is highly recommended.