Peanut butter is commonly used in bodybuilding primarily due to its nutritional profile, which has some scientific support. It is a calorie-dense food, rich in healthy monounsaturated and polyunsaturated fats, and provides a moderate amount of protein (about 7-8 grams per 2-tablespoon serving). For bodybuilders, especially those aiming for muscle gain (bulking), achieving a caloric surplus is often necessary, and peanut butter provides an accessible and palatable way to increase daily calorie intake without excessive food volume.

Additionally, peanut butter contains vitamins and minerals such as magnesium, potassium, and vitamin E, which are important for muscle function and overall health. While peanut butter is not a complete protein (it lacks sufficient amounts of some essential amino acids), when combined with other protein sources such as whole grains or dairy, it can contribute to meeting daily protein needs.

Scientific evidence supporting peanut butter’s use in bodybuilding is indirect, based primarily on nutritional science regarding macronutrient needs for muscle growth and repair. There are no direct clinical trials on peanut butter specifically enhancing muscle mass or performance, but its macronutrient composition makes it a practical food for athletes and bodybuilders. However, its high fat and calorie content may not be suitable for those in a cutting phase or aiming to reduce body fat.