Do You Need to Eat More if You Have Muscles? Understanding Calorie Needs

October 20, 2025 •

4 min read

According to the Mayo Clinic, people with more muscle mass burn more calories even at rest, a concept tied to a higher basal metabolic rate. This metabolic fact directly explains why you need to eat more if you have muscles, whether your goal is to build, maintain, or simply fuel a more active physique.

Quick Summary

This guide explains the metabolic reality that more muscle demands increased caloric and macronutrient intake. It covers how to strategically adjust your diet to support muscle growth and maintenance without unwanted fat gain.

Key Points

Metabolic Demand: Having more muscle mass increases your resting metabolic rate, meaning your body burns more calories at rest than someone with less muscle.
Calorie Surplus: To build new muscle tissue, a consistent, moderate calorie surplus (5–20% above maintenance) is necessary to provide the energy for growth.
Protein is Priority: Higher muscle mass requires more protein (1.6-3.1 g/kg) to fuel muscle protein synthesis and repair, making protein distribution key.
Fuel Your Training: Adequate carbohydrate intake is essential for powering intense resistance training and replenishing glycogen stores for optimal performance and recovery.
Smart Bulking: An uncontrolled, large calorie surplus does not speed up muscle growth and will primarily lead to unnecessary fat gain.
Undereating Risks: Not eating enough calories can cause the body to enter a catabolic state, breaking down muscle tissue for energy instead of building it.

The Metabolic Reality: Muscle vs. Fat

For decades, the conventional wisdom has been that muscle tissue is more metabolically active than fat tissue, and for good reason—it is. A larger, more muscular body requires more energy simply to exist, a measure known as your Basal Metabolic Rate (BMR). While the exact calorie burn per pound of muscle is debated, with some estimates ranging from 4.5 to 7.0 calories per pound per day, the principle remains: more muscle equals a higher metabolic furnace. This means that individuals with greater muscle mass have higher daily calorie requirements compared to someone of the same weight but with a higher body fat percentage. Your body needs a continuous supply of energy to power essential functions like organ function, and muscle tissue demands more fuel for its maintenance and repair cycles.

The Role of Caloric Surplus for Muscle Growth

While a higher metabolism means a higher maintenance calorie level, simply having muscles is not enough to grow them further. To build new muscle tissue (a process called hypertrophy), your body requires a consistent caloric surplus. This means you must consume more calories than you burn each day. For many, this surplus should be modest and controlled—often in the range of 5–20% above maintenance calories—to minimize excess fat gain. If the surplus is too large, the body will convert the excess energy into fat stores. The total number of calories needed to build a pound of muscle is also higher than what's contained within the muscle itself, as a significant amount of energy is expended in the process of muscle protein synthesis and repair.

Strategic Fueling for Muscle Gain

To fuel muscle growth effectively, consider these dietary strategies:

Prioritize Protein: Protein is the building block of muscle. For those lifting weights, research suggests a daily intake of 1.6 to 3.1 grams per kilogram of body weight is beneficial for maximizing muscle growth. Spreading this intake throughout the day can optimize muscle protein synthesis.
Don't Fear Carbs: Carbohydrates are the body's primary fuel source, especially for high-intensity exercise like weight training. Consuming adequate carbs ensures your body doesn't use precious protein for energy and helps replenish glycogen stores for better performance and recovery.
Embrace Healthy Fats: Dietary fats are crucial for hormone production, including testosterone, which is vital for muscle building. Aim for a moderate intake from sources like nuts, seeds, and avocados.
Meal Frequency: Eating 4-6 well-portioned meals and snacks daily can help provide a steady supply of nutrients, particularly protein, to your muscles.
Whole Foods Focus: Centering your diet on nutrient-dense, whole foods ensures you get the vitamins, minerals, and fiber needed to support intense training and overall health.

Comparing Dietary Needs: High Muscle vs. Low Muscle


Feature	High Muscle Mass Individual	Lower Muscle Mass Individual
Basal Metabolic Rate (BMR)	Higher due to more metabolically active tissue.	Lower, requiring fewer calories for resting functions.
Daily Calorie Needs	Higher for both maintenance and growth phases.	Lower baseline calorie requirements overall.
Protein Requirements	Higher per kilogram of body weight to maintain or increase mass.	Standard recommendations (0.8 g/kg) often sufficient, depending on goals.
Carbohydrate Needs	Higher to support intensive training and replenish glycogen stores.	Lower to moderate, based on activity level.
Nutrient Partitioning	More efficient at directing nutrients toward muscle tissue.	Prone to storing excess calories as fat more easily.
Calorie Surplus Strategy	Requires a more controlled, smaller surplus (5-20%) to avoid fat gain.	Can build muscle with minimal surplus initially but with slower rates.

The Pitfalls of Undereating and Overeating

Under-eating with significant muscle mass can have detrimental effects. If you're not consuming enough calories to meet your elevated metabolic demand, your body may enter a catabolic state, breaking down muscle tissue for energy. This undermines all your hard work in the gym. Furthermore, inadequate protein intake can halt muscle protein synthesis, preventing recovery and growth.

Conversely, overeating significantly, especially in an uncontrolled manner (often called a 'dirty bulk'), can lead to excessive fat gain. While a calorie surplus is necessary for growth, an overly large one simply results in more fat, not faster muscle gains. The body can only build muscle at a certain rate, and force-feeding it won't accelerate this biological process. As a result, strategic, controlled eating is key to maximizing lean mass gains.

Conclusion: Fueling Your Muscle Effectively

So, do you need to eat more if you have muscles? The answer is an unequivocal yes. More muscle mass increases your resting metabolic rate and, critically, your energy needs for building and maintaining that tissue. However, it's not a license to eat indiscriminately. The key lies in strategic fueling—consuming a modest calorie surplus to facilitate growth, prioritizing high-quality protein, and providing ample carbohydrates and healthy fats. By understanding your body's enhanced metabolic demands and implementing a smart nutrition plan, you can effectively fuel your muscles, maximize your training, and achieve your fitness goals. Your diet should be as intentional as your training, ensuring every meal works toward your progress, not against it. For more in-depth guidance, consider consulting resources from reputable organizations like the International Society of Sports Nutrition.

Frequently Asked Questions

The amount depends on your goals. For muscle maintenance, your caloric needs will be higher simply due to a higher resting metabolism. To build new muscle, a modest calorie surplus of 5-20% above your new maintenance level is recommended to promote growth without excessive fat gain.

Yes, having more muscle tissue increases your metabolism and your total daily energy expenditure, even at rest. This means a higher calorie burn throughout the day, which can aid in fat loss when combined with a proper diet.

While protein is critical for muscle repair and building, it is not the only factor. A sufficient calorie surplus is necessary to provide the energy for muscle synthesis. You also need carbohydrates to fuel your workouts and healthy fats for hormone function.

Referred to as 'body recomposition,' this is possible, especially for beginners or those returning to training. It requires a precise balance of a high-protein diet, strength training, and a controlled calorie intake. More advanced lifters typically focus on one goal at a time (bulking or cutting).

If you don't eat enough to support your muscle mass, your body may start breaking down muscle tissue for energy in a catabolic process. This can lead to muscle loss, decreased strength, and a slower metabolism.

With age, metabolism naturally slows, and muscle loss can occur more easily. Older adults may need to slightly increase their protein intake (to around 1g/kg) and maintain resistance training to help prevent sarcopenia (age-related muscle loss).

Yes, the principle is the same for women. Muscle tissue is metabolically active regardless of gender. A woman with significant muscle mass will have a higher resting metabolic rate and require more calories and protein to fuel her body and training than a woman of similar size with less muscle mass.