Ever grab a snack but then feel hungry again 20 minutes later? Next time, reach for a banana. It’s loaded with Resistant Starch RS, a healthy carb that fills you up and helps to boost your metabolism. Slightly underripe medium-sized bananas have 12.5 grams of RS—more than most other foods. Ripe bananas give you 4.7 grams of RS, still enough to keep hunger pangs away.