content: Obesity is about malnutrition and insulin levels. Just try to over eat beef: your body tells you when to stop. It's time to quit eating when you're pl  ff8  anning your bites. When we eat fiber rich foods which expand in the stomach and contain little protein or fat, our bodies know that food is not nutritious and tell us to eat until full, whereas if you just ate the burger patties at McDonald's you'd be full after 8 or 9, even less if you didn't trick your mouth with ketchup.