Do I Need Carbs to Get Bigger? The Scientific Guide to Muscle Growth

December 26, 2025 •

2 min read

Research indicates that adequate carbohydrate intake is essential for maximizing performance during high-intensity exercise and supporting muscle growth. So, do I need carbs to get bigger? For anyone serious about gaining mass, the answer is a definitive yes, and it's backed by the science of fueling your body effectively.

Quick Summary

Carbohydrates are a primary fuel for intense training, helping to replenish muscle glycogen stores depleted during workouts. This intake ensures energy for performance, supports protein utilization for repair, and influences hormonal balance to promote an optimal anabolic environment for maximizing muscle gains.

Key Points

Carbs Fuel Intense Workouts: Glycogen, the stored form of carbs, is the primary fuel for high-intensity training, directly impacting your ability to lift heavy and stimulate muscle growth.
Carbs Spare Protein: Sufficient carb intake prevents your body from breaking down muscle protein for energy, ensuring that protein is used exclusively for muscle repair and building.
Insulin Drives Muscle Growth: Carbohydrates trigger an insulin response, which acts as an anabolic hormone by transporting nutrients to your muscle cells to aid recovery and synthesis.
Timing Matters for Performance: Strategic timing of carb intake, particularly pre- and post-workout, maximizes energy availability and accelerates the recovery process.
Quality Carbs Provide Sustained Energy: Prioritizing complex, nutrient-dense carbohydrate sources provides the steady energy required for muscle growth and overall health.
High-Carb Diets Favor Hypertrophy: Compared to low-carb diets, a higher-carbohydrate approach is shown to be more effective for maximizing muscle and strength gains in resistance-trained individuals.

The Core Role of Carbohydrates

To understand why carbohydrates are so critical for muscle growth, it's essential to look at what they do inside the body. When you consume carbs, they are broken down into glucose, which is then stored in your muscles and liver as glycogen. This glycogen is your body's primary and most readily available fuel source, particularly during high-intensity activities like weightlifting. Think of glycogen as the high-octane fuel for your muscular contractions.

The Glycogen Connection: Fueling Peak Performance

Intense resistance training rapidly depletes muscle glycogen stores. Low glycogen levels can hinder performance, as fat is unable to provide energy as quickly as needed for high-intensity movements. Sufficient glycogen allows for heavier lifts and more reps, supporting progressive overload and muscle growth.

The Protein-Sparing Effect

Insufficient carbohydrate intake can lead the body to use muscle protein for energy, rather than for repair and building. Adequate carbs ensure protein is utilized for muscle growth.

Insulin's Anabolic Role

Carbohydrate consumption releases insulin, an anabolic hormone that transports nutrients like amino acids and glucose into muscle cells, promoting muscle protein synthesis and recovery.

The Timing of Your Carbohydrate Intake

Strategic carb timing can significantly benefit training and recovery.

Pre-Workout: Complex carbs 1-3 hours before training provide sustained energy.
During Workout: Simple carbs can maintain performance during long or high-volume sessions.
Post-Workout: Simple carbs and protein after training replenish glycogen and support recovery.

Comparison: High-Carb vs. Low-Carb for Bodybuilding

Research indicates differences in high-carb and low-carb diets for resistance-trained men.


Feature	High-Carbohydrate Diet	Low-Carbohydrate Diet
Primary Fuel Source	Glucose from carbohydrates	Fat/ketones
Training Performance	Supports higher intensity and volume training	Can hinder high-intensity performance due to lower glycogen
Muscle Growth	Supports greater muscle hypertrophy	Potential for hindered growth due to protein being used for energy
Fat Loss	Effective when in a calorie deficit; may feel less restricted	Very effective for initial fat loss and creating a deficit
Hormonal Response	Optimal insulin response for anabolic signaling	Suppressed insulin; potential for elevated cortisol
Recovery	Rapidly replenishes glycogen stores post-workout	Slower glycogen replenishment, potentially impacting subsequent workouts

A high-carbohydrate approach typically results in greater muscle and strength gains compared to low-carb diets for muscle growth.

Choosing the Right Carbs

Focus on nutrient-dense sources:

Complex Carbohydrates: Whole grains, starchy vegetables, legumes for sustained energy.
Simple Carbohydrates: Fruits, white rice for quick post-workout recovery.

Putting It All Together for Maximum Gains

Carbohydrates are part of a larger plan including protein, a caloric surplus, and adequate sleep. Optimal carb intake varies individually, but a balanced approach is key.

Conclusion

For muscle growth, carbs are essential. They fuel workouts, spare protein, and create an anabolic environment. Strategic carb intake supports performance, recovery, and ultimately, getting bigger and stronger.

Frequently Asked Questions

No, carbs are not bad for building muscle. In fact, they are essential. They provide the energy needed for intense workouts, spare protein from being used as fuel, and stimulate insulin to help drive muscle protein synthesis. They are a critical component of an effective muscle-building diet.

If you don't consume enough carbohydrates, your body's muscle glycogen stores will be low. This can lead to decreased performance and fatigue during workouts. In a severe deficit, your body may start breaking down muscle tissue for energy, hindering your growth and recovery efforts.

Simple carbs are digested quickly for a rapid energy boost, making them ideal for fueling immediately before or after a workout. Complex carbs are digested slowly, providing sustained energy for longer durations and filling your glycogen stores for overall performance.

The ideal amount varies based on individual factors, but general guidelines for athletes and bodybuilders suggest getting a large portion of daily calories from carbohydrates. A common recommendation is 3-5 grams per kg of body weight or more, depending on activity level.

For most resistance training sessions, ensuring adequate carbs throughout the day is sufficient. Carb-loading is more common for endurance athletes to maximize glycogen stores before an event, but a solid meal 1-3 hours before a heavy lifting session is a great strategy.

While it is possible to gain muscle on a ketogenic diet, research suggests high-carbohydrate diets are superior for maximizing muscle and strength gains in resistance-trained individuals. This is primarily due to better workout performance and the anabolic effects of insulin.

Yes, especially post-workout. Combining carbohydrates with protein can accelerate glycogen replenishment and enhance muscle protein synthesis, leveraging insulin's nutrient-shuttling effects for optimal recovery.