Under normal circumstances, leptin and insulin in the human body can help people control their mouths, and once they are full, they will send a signal to the brain to tell people to stop eating. And junk food contains excessive saturated fat, which will be blocked by saturated fat molecules. Sign to stop eating. It follows that:. ['Overall balanced diet and maintaining nutrition is the most critical factor for maintaining health.', 'Junk food not only causes obesity, but also induces other diseases.', 'Saturated fats in junk food far exceed other foods.', 'The signal of fullness is transmitted to the brain to avoid overeating.']