Peanut butter packs 8 grams of protein and 4 grams of fiber per serving, making it an ideal snack to help you fill your stomach and stay satisfied. Remember to take a look at the ingredients label of your peanut butter, which should include nothing but peanuts and salt. A review of research published by the Journal of Food Science and Technology highlights the fact that peanut butter can help people feel more satisfied compared to other snacks.