Nutrition for muscle gain: how much to eat, what to eat, and how to plan your week

Muscle gain isn't just about training. Without a properly structured diet, even the smartest gym programme will deliver minimal results. In this article you will find specific guidelines on calories, protein, carbohydrates and fats, along with a ready-made weekly nutrition plan for muscle growth.

Why nutrition determines your muscle gain results

Muscles are not built out of thin air. For muscle tissue to grow, the body needs two key resources: building material (protein and amino acids) and sufficient energy. Training merely creates the stimulus — micro-damage to fibres that the body repairs with a surplus. But recovery and growth only happen when nutrition supplies the necessary resources.

If you train intensely but eat in a calorie deficit, your body uses muscle protein as an energy source. Anabolic processes are blocked — the body switches into survival mode rather than growth mode. This is one of the most common mistakes beginner athletes make.

The hormonal side of the picture matters too. Chronic undereating lowers testosterone and insulin-like growth factor IGF-1 — two key anabolic hormones. Adequate calorie intake keeps hormone levels at a point that supports growth. That is why a muscle-building diet is not only about "how much protein" but also about overall satiety and energy balance.

If you want to understand how to structure a training programme aimed at muscle gain, read the article F/AI for muscle gain: how an AI trainer builds a programme around your goals.

How to calculate your daily calorie needs for muscle growth

The starting point is your basal metabolic rate (BMR): the number of calories the body burns at complete rest. The Mifflin–St Jeor formula is most commonly used to calculate BMR. BMR is then multiplied by an activity factor:

1.2 — sedentary lifestyle
1.375 — light activity (1–3 workouts per week)
1.55 — moderate activity (3–5 workouts)
1.725 — high activity (6–7 workouts)

The resulting number is your maintenance calorie level (TDEE). For muscle gain, a surplus is added on top of it. The optimal range is +250–500 kcal per day. This is a moderate excess that supports growth without excessive fat accumulation.

Why not more? Muscles can only be synthesised at a limited rate. Calories beyond that threshold are stored as fat tissue, not muscle. A realistic rate of gain for a natural athlete is around 1–2 kg per month, provided training and nutrition are well managed.

Monitor your progress: weigh yourself in the morning on an empty stomach 2–3 times a week and average the readings. If your weight has not increased in 2 weeks, add 100–150 kcal. If it is rising too fast (more than 1 kg per week), reduce slightly.

Protein: the key nutrient for muscle tissue growth

Protein is the foundation of a muscle-building diet. The amino acids it is made of serve as the literal building material for muscle fibres. Without sufficient protein, muscle protein synthesis is impossible, even when calories are adequate.

According to a meta-analysis published in the British Journal of Sports Medicine in 2018, the optimal protein intake for maximum muscle growth is 1.6–2.2 g per kg of body weight per day. For people with excess body fat, it is better to calculate based on lean body mass.

Protein quality is no less important than quantity. Complete sources — animal products (meat, fish, eggs, dairy) — contain all essential amino acids in the right proportions. Plant sources (legumes, soy, nuts) often have an incomplete amino acid profile, so when following a vegan diet it is important to combine different sources.

A practically important point: distribute protein evenly across 3–5 meals. According to research published in the Journal of Nutrition in 2014, 20–40 g of protein per meal is the optimal dose for stimulating muscle protein synthesis. Trying to get it all in one sitting is inefficient.

For more detail on protein requirements for different goals, read the article How much protein you need per day: guidelines for weight loss, muscle gain and maintenance.

Carbohydrates: fuel for training and recovery

Carbohydrates are the primary energy substrate during strength training. They are stored in muscles and the liver as glycogen. When glycogen is depleted, training intensity drops and recovery slows.

There are two types of carbohydrates:

Slow (complex) — grains, vegetables, wholegrain bread. Provide a stable energy level throughout the day.
Fast (simple) — fruit, honey, white rice. Absorbed quickly and especially useful before and immediately after training.

Before training (1.5–2 hours prior), it is optimal to eat a portion of complex carbohydrates with protein — this tops up glycogen and supports performance. After training, fast carbohydrates combined with protein help restore glycogen more quickly and kick-start recovery.

The "carbohydrate window" is often overstated: if you eat regularly and consume enough carbohydrates throughout the day, the urgency of a 30-minute window is reduced. However, when training fasted or doing double sessions, eating quickly after exercise genuinely matters.

Recommended carbohydrate intake during a muscle-gain phase is 4–6 g per kg of body weight per day, depending on training intensity.

Fats in a muscle-gain diet: not an enemy, but a partner

Fats are unfairly regarded as the athlete's enemy. In reality they perform critically important functions for muscle growth. Most importantly, they are involved in the synthesis of sex hormones, including testosterone. Diets with very low fat content (below 15% of total calories) lower testosterone levels, which directly inhibits anabolism.

In a muscle-building diet, fats should account for 20–35% of total calorie intake. It is important to maintain a balance between types:

Saturated (meat, dairy) — in moderation, do not eliminate entirely
Monounsaturated (olive oil, avocado) — the backbone of the diet
Polyunsaturated, omega-3 (fatty fish, flaxseed oil) — a priority

Omega-3 fatty acids reduce inflammation after intense exercise and speed up recovery. According to the Journal of the International Society of Sports Nutrition in 2011, 2–4 g of EPA and DHA per day may support muscle protein synthesis.

The best foods for muscle gain

When putting together an athlete's nutrition plan, base it on these food categories:

Protein sources:

Chicken breast, turkey
Cottage cheese (5–9% fat)
Eggs (whole eggs + egg whites)
Salmon, tuna, cod
Lentils, chickpeas, kidney beans

Carbohydrate sources:

Oats, buckwheat, brown rice
Potatoes, sweet potatoes
Wholegrain bread and pasta
Bananas, dates (around workouts)

Sources of healthy fats:

Avocado
Walnuts, almonds, cashews
Extra-virgin olive oil
Mackerel, herring, salmon

Limit:

Alcohol (reduces protein synthesis and testosterone)
Trans fats (fast food, margarine)
Excess simple sugars outside of training context

Meal timing: how many times a day should you eat when gaining muscle

The optimal meal frequency for maintaining anabolism is 4–5 times per day. This allows you to distribute protein evenly and maintain a stable level of amino acids in the blood.

Breakfast is especially important: after overnight fasting, amino acid levels are reduced and the body needs protein to slow catabolism. Include eggs, cottage cheese or a protein shake.

Before training (1.5–2 hours prior): a portion of complex carbohydrates plus protein. For example, buckwheat with chicken breast or oats with eggs.

After training: protein plus fast carbohydrates. A classic option is cottage cheese with banana or rice with fish.

Before bed: casein protein or regular cottage cheese — it is absorbed slowly and feeds muscles throughout the night. This is especially relevant during an active muscle-gaining phase.

If you want to track how your nutrition aligns with your training progress, take a look at how workout tracking in F/AI works — it helps you see the connection between workload and recovery.

A sample weekly nutrition plan for muscle gain

Below is a basic diet structure. Specific portions depend on your TDEE and target calorie intake.

Monday – Friday (training days)

Meal	Foods
Breakfast	100 g oats, 3 eggs, a handful of berries
2nd breakfast	200 g cottage cheese, banana
Lunch	150 g buckwheat, 200 g chicken breast, vegetables
Pre-workout	100 g rice, 150 g tuna
Post-workout	Protein shake or cottage cheese, 80 g white rice
Dinner	180 g salmon, 150 g potatoes, salad
Before bed	150 g cottage cheese

Saturday – Sunday (rest days)

Reduce carbohydrates by 20–30%, but keep protein at the same level. Focus on slow carbohydrates, vegetables and fatty fish.

For guidance on how to build a training programme to go alongside this kind of diet, read the article How to build a training programme on your own.

Frequently asked questions about nutrition for muscle gain

Do you need sports supplements when gaining muscle?

Sports supplements are additions, not the foundation of your diet. Protein shakes are convenient when it is difficult to hit your daily protein target from whole food alone. Creatine monohydrate has a proven evidence base for improving strength performance (meta-analysis in the Journal of Strength and Conditioning Research, 2017). Everything else is secondary. Build your diet around whole foods first, then add supplements if needed.

Can you gain muscle without meat?

Yes, with careful planning. Key plant-based protein sources are soy and soy products, lentils, chickpeas, quinoa and seitan. To achieve a complete amino acid profile, combine legumes with grains. Lacto-vegetarians and pescatarians have it considerably easier: eggs, dairy and fish cover most needs. Keep an eye on vitamin B12, iron and zinc levels — they are less readily absorbed from plant sources.

When is it better to eat carbohydrates — before or after training?

Both. Before training, carbohydrates top up glycogen and support performance. After training, they accelerate glycogen restoration and create an anabolic environment when combined with protein. There is no need to choose one or the other: distribute carbohydrates around your workout and throughout the day, based on 4–6 g per kg of body weight.

How should you eat for muscle gain after the age of 40?

With age, muscle protein synthesis slows, so protein requirements increase towards the upper end — 2–2.2 g per kg. It is important to monitor fat quality and avoid an excessive surplus, in order to minimise fat accumulation. For more on the specifics of training at this age, see the article Fitness after 40: how to train to lose fat and build muscle without harming your joints.

How do you know if you are eating enough for muscle growth?

Use three indicators: body weight (should be rising slowly — 0.5–1 kg per month), strength levels (should be increasing), and how you feel and recover (fatigue, sleep, mood). If you are training regularly but your weight is stalled and your strength is not improving, you are most likely not eating enough. Keep a food diary for at least the first 4–6 weeks.

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