caption: Slide 3 of 4: Leptin is essentially ghrelin's mirror image. A natural appetite suppressant, it's low when you're hungry and rises once you are full. A diet high in fried, fatty, and sugary foods can interfere with leptin and prevent your body from noticing when you've had enough to eat. This can naturally make you gain weight as a result of ``leptin resistance.'' To counteract this, make sure you eat a balanced diet and follow these rules to prevent weight gain.