Fueling Your Body for Athletic Success: Eating for Muscle Gain

Weight loss and cutting calories tend to steal the limelight when it comes to information on how to best fuel your body for athletic success. However, not every athlete wants to lose weight. Many athletes are looking to put on weight in the form of lean muscle tissue to improve body composition and power output.

Eating for gains is unique from eating for bodyweight maintenance or loss. Muscle building is an anabolic process, meaning the body is creating tissue (1). A body has more than 600 muscles, so adding to that mass requires extra calories (1, 2).

Of course, if you just load up on calories alone, the weight gain might be more fat mass than lean tissue mass. It is important to eat the right combination of high-quality foods (particularly enough protein) while continuing to push yourself physically to make the extra calories work for, not against, your goals (2).

CONSUMING ENOUGH CALORIES

If you do not consume the amount of calories needed to support general health and the additional energy output of training, the body may be forced to tap into stored energy (3). This is a catabolic (breaking down) process, while gaining is the exact opposite: anabolic (building up) (1).

To build additional muscle mass, your body requires extra calories (2). The exact amount of calories needed for health, activity, and gain goals varies from person to person. To get a good estimate of overall metabolic needs, plug your current information and goals accurately into an energy tracking app, such as MyFitnessPal to ensure you are consuming enough.

CONSIDERING CARBS AND FAT

Protein gets all the attention when it comes to muscle mass, but neglecting healthful fats and complex carbohydrates stalls your lean tissue gains. Carbohydrates are required for energy production (2). Skimping on starchy vegetables, grains, and fruit leaves you feeling too fatigued to execute the physical training required to stimulate muscle growth (2). Drastically restricting carbohydrates forces your body into utilizing stored amino acids for energy, taking away from your muscle mass (4, 5). These macronutrients also contain vitamins, minerals, and phytonutrients to allow the metabolic process of tissue growth to occur.

DIVERSIFYING YOUR PROTEIN INTAKE

This macronutrient provides amino acids, the building blocks of tissues, to your body. Protein needs increase when aiming to gain muscle. Many athletes associate protein intake with animal intake. Animal foods are an effective source of protein, as they contain the essential amino acids needed for muscle building (6). Plant proteins can also be a great source. Compared with animal protein, plant protein may contain fewer total amino acids and may be deficient in specific amino acids (6). Whole-plant protein sources are typically rich in beneficial nutrients that can aid performance gains. Plenty of plants contain protein and should not be overlooked. For example, oatmeal is considered a carbohydrate but actually contains 5 grams of protein per cooked cup (7). Lentils, beans, tofu, tempeh, edamame, hummus, mung bean sprouts, quinoa, buckwheat, and nuts can all provide protein that stimulates muscle synthesis to maintain or grow a lean body.

For best results, consider taking in a variety of protein sources and emphasize plant sources. Regardless of the source, protein should be an area of focus as consuming enough is important for muscle maintenance, growth, regulating your appetite, and performance (2).

When it comes to eating for performance and body composition, there are always strategies and supplements that may be able to provide an extra boost.

Leucine is an amino acid essential for stimulating muscle building (6). Aim to consume foods high in leucine such as milk, cheese, chicken, and fish (8). Consuming a branched-chain amino acid supplement containing leucine before, during, or after endurance training might help prevent muscular breakdown (9).

There is also evidence that consuming a large dose of casein, a slow-digesting protein, before bed can improve muscle synthesis overnight, meaning your body is working toward your gain goals while you sleep (10). Being dehydrated might create the look of lean muscles, but this is deceptive. Muscle tissue stores more water than fat tissue. To help your muscles grow, drink more H2O (11)!

When considering your dietary choices as an athlete, it is crucial to determine your goals — aesthetics, performance, and health — and choose the types of foods and amounts that correlate with those goals. If you are struggling to match intake with your body and performance goals, reach out to a board-certified sports dietitian who can assist you in building a personalized plan.

Originally published January 2020; Updated October 2025