Nutrition Diet: What to eat to increase body size?

October 22, 2025 •

4 min read

According to research published in the Journal of the International Society of Sports Nutrition, consuming enough high-quality protein and maintaining a calorie surplus is essential for increasing lean muscle mass and is a primary factor in what to eat to increase body size. But beyond just protein, a balanced intake of all macronutrients is crucial for sustainable and healthy gains.

Quick Summary

This guide details the specific nutrient-dense foods and dietary strategies essential for building body size through muscle gain. It covers the importance of a calorie surplus, the optimal balance of protein, carbohydrates, and healthy fats, and provides food examples, meal timing tips, and practical advice for fueling muscle growth effectively.

Key Points

Calorie Surplus is Essential: To gain body size, you must consume more calories than you burn daily, providing your body with the necessary energy for muscle growth.
Protein is the Building Block: Include high-quality protein sources like lean meats, eggs, and dairy in every meal to support muscle repair and synthesis.
Carbs Fuel Your Workouts: Complex carbohydrates from sources like whole grains and starchy vegetables provide sustained energy for intense training sessions.
Healthy Fats Add Calories: Incorporate energy-dense foods rich in healthy fats, such as nuts, seeds, and avocados, to easily increase your calorie intake.
Timing Matters for Recovery: Eat a mix of protein and carbs before and, especially, after your workout to optimize muscle glycogen replenishment and recovery.
Hydration and Rest are Crucial: Proper hydration and adequate sleep are often overlooked but are vital for muscle function, recovery, and overall growth.

The Foundational Principles of Healthy Body Size Increase

To increase body size, particularly muscle mass, the fundamental requirement is to consistently consume more calories than your body burns—a state known as a calorie surplus. Aim for a modest surplus of 300–500 extra calories per day for steady, healthy growth, or 700–1000 for faster gains. This surplus, when combined with a consistent resistance training program, provides the energy your body needs to build new muscle tissue rather than just storing fat.

The Role of Macronutrients

Protein: This is the building block of muscle tissue. High-quality protein sources, containing all nine essential amino acids, are vital for repairing and building muscle fibers after exercise. Spread your protein intake throughout the day to maximize muscle protein synthesis.
Carbohydrates: Your body's primary fuel source, carbohydrates are stored as glycogen in your muscles and liver. They provide the energy needed for intense workouts and are crucial for refueling muscles post-exercise to kickstart recovery. Focus on complex carbohydrates for sustained energy.
Healthy Fats: Energy-dense and vital for hormone production and overall health, healthy fats aid in nutrient absorption and provide a significant calorie boost. They also help fight inflammation and support heart health.

Food Choices for Fueling Growth

Focus on a variety of nutrient-dense foods to ensure you get all the vitamins and minerals necessary for optimal performance and recovery.

Protein Sources

Lean Meats and Poultry: Chicken breast, lean ground beef, and salmon are excellent sources of high-quality protein and other vital nutrients like iron.
Dairy: Greek yogurt, cottage cheese, and whole milk offer a great balance of protein, carbs, and fats. Cottage cheese, in particular, is a protein-rich snack.
Eggs: A complete and highly digestible protein source that contains leucine, an amino acid crucial for muscle building.
Legumes and Beans: Lentils, chickpeas, and black beans provide a plant-based source of protein, fiber, and complex carbohydrates.

Complex Carbohydrate Sources

Whole Grains: Brown rice, quinoa, and oats provide sustained energy and a better net protein balance compared to refined grains.
Starchy Vegetables: Sweet potatoes, potatoes, and winter squash are excellent sources of carbs that also replenish muscle glycogen stores.
Fruits: Bananas, berries, and oranges offer quick-digesting carbs, vitamins, and antioxidants.

Healthy Fat Sources

Nuts and Seeds: Almonds, walnuts, and pumpkin seeds are calorie-dense and rich in healthy fats, protein, and fiber.
Avocado: A fantastic source of healthy monounsaturated fats and essential vitamins.
Oils: Extra virgin olive oil and avocado oil can easily add healthy calories to meals.

Homemade Weight Gain Shakes

For those who find it difficult to eat enough calories throughout the day, homemade shakes offer a convenient and nutritious solution. Here is a great example:

High-Calorie Shake: Blend 1.5 cups of whole milk with 1 banana, 1/2 cup rolled oats, 2 tablespoons of peanut butter, and 1 scoop of whey protein powder. You can also add chia or flax seeds for extra nutrients. This combination provides a powerful mix of calories, protein, carbs, and healthy fats.

Comparison of Whole Grains vs. Refined Grains


Feature	Whole Grains (e.g., Brown Rice, Oats)	Refined Grains (e.g., White Rice, White Bread)
Nutrient Density	Higher in fiber, vitamins, and minerals.	Lower in fiber and stripped of many nutrients during processing.
Energy Release	Slow, sustained energy release, preventing energy crashes.	Fast, rapid energy spike followed by a crash due to quick digestion.
Satiety	Keeps you feeling fuller for longer due to high fiber content.	Doesn't provide lasting fullness, potentially leading to overeating.
Muscle Impact	Supports higher protein turnover and net protein balance.	Less beneficial for muscle protein balance.
Digestion	Aids digestive health with its high fiber content.	Can be less beneficial for digestive health.

Timing and Habits for Optimal Growth

Timing your meals and focusing on key habits can significantly impact your results. Eating every 2-4 hours, including 3 balanced meals and several snacks, helps ensure a consistent energy supply and steady nutrient intake to support muscle synthesis.

Pre-Workout Nutrition: Consume a mix of protein and carbs before a workout to fuel your performance. Oatmeal with nuts and protein powder is a great option.
Post-Workout Nutrition: Within an hour of exercise, consume a meal or shake with protein and fast-acting carbs to replenish glycogen stores and aid muscle repair. A protein shake with fruit is ideal.
Stay Hydrated: Water is critical for muscle growth and recovery. It aids in protein synthesis, transports nutrients, and lubricates joints. Dehydration can hinder performance and recovery. Drink water throughout the day, not just during workouts.
Prioritize Sleep: Aim for 7-8 hours of quality sleep per night. This is when your body does most of its repair and muscle-building work.

Conclusion

Increasing body size requires a strategic, disciplined approach that goes beyond just eating more. By prioritizing a calorie surplus filled with nutrient-dense foods, focusing on high-quality protein, complex carbohydrates, and healthy fats, and incorporating supportive habits like proper hydration and sufficient sleep, you can effectively and healthily build muscle mass. The key is to be consistent with both your nutrition and resistance training. By following these principles, you will be well on your way to achieving your body size goals safely and sustainably.

For more in-depth information on healthy weight gain and nutrition, visit the Healthline article on How to Gain Weight.

Frequently Asked Questions

For steady and healthy weight gain, aim for a calorie surplus of 300–500 calories above your maintenance level. For faster gains, a surplus of 700–1000 calories may be appropriate, combined with resistance training.

Homemade protein shakes give you complete control over the ingredients, allowing you to pack them with nutrient-dense foods like oats, nuts, and healthy fats alongside your protein source. While supplements can be convenient, whole foods are generally preferred for optimal nutrition.

Yes, eating smaller, more frequent meals (every 2-4 hours) can be an effective way to meet your high calorie and protein requirements without feeling overly full. It helps maintain a steady supply of nutrients for muscle growth.

High-quality animal products like lean meats, eggs, and dairy are considered complete proteins, containing all essential amino acids. Plant-based sources like soy and quinoa are also complete, while others like beans and lentils can be combined to form a complete amino acid profile.

Yes, it is possible to build muscle on a plant-based diet. By combining different plant protein sources, such as legumes, nuts, and soy products like tofu, you can obtain a complete amino acid profile necessary for muscle synthesis.

Micronutrients are crucial for numerous body processes, including energy production, muscle function, and recovery. They play a supporting role in muscle growth and overall health, so ensure a varied diet rich in fruits, vegetables, and whole grains.

Avoid relying on excessive junk food for calories, skipping meals, neglecting resistance training, and drinking too many sugary drinks. Focus on nutrient-dense foods, consistent eating, and proper exercise for sustainable results.