Peanut butter is scientifically validated as a food that can support weight gain, primarily due to its high energy density and nutrient content. Each tablespoon of peanut butter provides approximately 90-100 calories, along with healthy fats (mainly monounsaturated and polyunsaturated), protein, and essential micronutrients such as vitamin E, magnesium, and niacin. Several research studies and clinical guidelines recognize calorie-dense foods like nut butters as effective for individuals seeking to increase body weight, including underweight adults or children, and those recovering from illness or experiencing malnutrition.

For example, peanut butter is commonly included in therapeutic feeding programs for malnourished children, often in the form of ready-to-use therapeutic food (RUTF) products, which are peanut-based pastes. These interventions are endorsed by organizations such as the World Health Organization and UNICEF, based on substantial clinical evidence that such formulations promote healthy weight gain and recovery from malnutrition.

In addition, general dietary guidance for people aiming to gain weight healthfully often highlights peanut butter as a practical option due to its palatability, versatility, and ease of incorporation into meals and snacks. While peanut butter alone is not a miracle solution, its nutrient profile and energy density make it a scientifically supported choice for promoting weight gain as part of a balanced, calorie-surplus diet.