Can You Build Muscle on Keto? What Science Says

“Can you build muscle on keto?”

This question regularly comes up in health and fitness circles. 

Some say building muscle on keto is nigh-on impossible because you need carbs to fuel workouts and expedite the muscle-building process.

Others disagree, claiming gaining muscle on keto is perfectly possible, provided you know how to eat and train to drive muscle gain.

Who’s right?

Can you gain muscle on keto?

And if so, how do you build muscle on keto?

Get evidence-based answers to these questions and more in this article.

Table of Contents

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• What Is the Keto Diet?
• Can You Gain Muscle on Keto?
• How to Build Muscle on Keto

What Is the Keto Diet?

The ketogenic, or “keto,” diet is a dietary regimen where you drastically reduce your carbohydrate intake, prompting your body to enter a metabolic state called ketosis. 

During ketosis, your body uses its fat reserves for energy by converting fat into ketone bodies in the liver, which serve as an alternative fuel source to glucose.

On a typical keto diet, most of your calories come from your fat intake, with fats making up 70-to-80% of daily calories, followed by 10-to-20% and 5-to-10% from protein and carbs, respectively. 

In most cases, people follow the keto diet because they believe it helps you lose fat.

Can You Gain Muscle on Keto?

Many studies have explored the connection between the ketogenic diet and muscle growth.

One older 11-week study that keto enthusiasts often cite as proof keto diets significantly boost muscle gain was conducted by scientists at The University of Tampa.

In this study, keto dieters gained twice as much muscle and lost about 30% more fat than non-keto dieters.

The problem is the scientists never released their full writeup, so it’s impossible to scrutinize the data to see if the results are reliable. Additionally, the researchers responsible have a history of fabricating results, having authored a paper claiming HMB is more potent than steroids.

The scientists also had the keto dieters “carb load” at the end of the study. This would’ve rapidly increased glycogen and water storage, which would’ve registered as lean mass in the final analysis and skewed the results.

As such, it’s prudent to approach this paper cautiously. Thus, the question lingers: can you build muscle on keto?

Let’s review the most recent research to find out. 

Study #1: Efficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trial.

One study often cited by keto critics as evidence the keto diet hinders muscle growth was published in the Journal of the International Society of Sports Nutrition. 

In the study, 24 experienced male weightlifters underwent an 8-week strength training program while bulking on either a keto or non-keto diet.

The diets aimed to provide ~18 calories and ~0.9 grams of protein per pound of body weight per day. The keto group got 10% of their calories from carbs and 70% from fats, whereas the non-keto group consumed 55% from carbs and 25% from fats.

The study showed that, despite supposedly being in a calorie surplus, the keto group lost an average of 0.8kg of body fat and gained no muscle. In contrast, the non-keto group gained ~3 pounds of muscle without gaining fat.

While the researchers took these results as evidence that the keto diet impairs muscle growth, this probably isn’t a fair conclusion. Since the dieters lost fat and gained no muscle on the keto diet, it’s likely they were in a calorie deficit, so we shouldn’t draw conclusions about how the keto diet affects bulking. 

One possible reason for this outcome is that the scientists only provided the keto dieters with guidelines on what they should eat, not with food. Since studies show that the keto diet can curb appetite, it’s very possible that the keto dieters simply couldn’t eat enough calories daily to build muscle effectively. 

Study #2: Effects of a ketogenic diet on body composition and strength in trained women.

In another study by the same researchers, 22 experienced female weightlifters trained 4 times weekly and followed either a keto or non-keto diet for 8 weeks.

During the study, the keto dieters ate 30-to-40 grams of carbohydrates daily, with at least 0.8 grams of protein per pound of body weight distributed across 3-to-6 meals. The non-keto dieters ate ~0.5 grams of fat and at least 0.8 grams of protein per pound of body weight per day, with the remaining calories coming from carbs.

Importantly, neither group had to control their total daily calorie intake.

Similarly to the previous study, the results showed that the keto diet led to more fat loss and less muscle gain than non-keto dieting. Furthermore, the non-keto dieters tended to gain more strength than those in the keto diet group. 

Again, these findings suggest that the non-keto group could maintain a calorie surplus and, thus, gain muscle. However, keto dieting seemed to make eating enough food to effectively gain muscle challenging, leading the authors to deem the keto diet as “suboptimal” for bulking.

Study #3: Effects of Two Months of Very Low Carbohydrate Ketogenic Diet on Body Composition, Muscle Strength, Muscle Area, and Blood Parameters in Competitive Natural Body Builders.

In this study, 19 competitive male bodybuilders underwent their regular training regimen and followed either a keto or a non-keto diet for 8 weeks. 

All the dieters ate the same amount of protein—1.1 grams per pound of body weight per day. However, the keto dieters got 5% of their calories from carbs, while the non-keto dieters got 55% of their calories from carbs.

The results showed that the keto dieters lost a small amount of fat, whereas the non-keto dieters gained a small amount. Additionally, the keto dieters gained almost no muscle, while the non-keto dieters gained around 5 pounds of muscle. 

Moreover, both groups gained about the same amount of strength. 

Compared to the non-keto dieters, the keto dieters improved several health markers, including triglyceride, HDL cholesterol, and glucose and insulin levels, though they also experienced a slight decrease in “anabolic” (muscle-building) hormones, including testosterone and insulin-like growth factor 1.

At first blush, these results suggest that while the ketogenic diet might promote fat loss and favorably change some cardiovascular and metabolic health markers, it probably isn’t the most effective diet for gaining muscle. 

There’s a caveat, though: this study measured body composition changes using DEXA. 

While DEXA scans provide reasonably accurate data about fat and muscle changes, they’re sensitive to changes in water weight. This is significant when studying low-carb diets because those eating carbs store more water than those who eliminate carbs. 

Therefore, changes in muscle mass may be a mistake since rapid water loss appears very similar to muscle loss on a DEXA scanner’s results. 

Nonetheless, the fact remains: keto diets appear to make consuming enough calories to maximize muscle gain difficult.

How to Build Muscle on Keto

The above research indicates that while the keto diet can effectively help you lose weight, it isn’t optimal for muscle growth.

The main challenge with following a keto diet is that it’s hard to eat enough calories to get your body’s “muscle-building machinery” working at full capacity. 

That doesn’t mean you can’t build muscle while on keto—you just have to pay special attention to a few key aspects of your diet and training. 

1. Eat enough calories. 

Aim for around 110% of your total daily energy expenditure to optimize muscle growth while limiting fat gain.

For most, this equates to 16-to-18 calories per pound of body weight per day.

To get more detailed information on exactly how many calories you should eat to gain muscle effectively, take the Legion Diet Quiz.

2. Eat the right balance of macronutrients.

In addition to eating the right number of calories, optimizing your carbs, fat, and protein intake is vital. Here are some good guidelines:

• Carbs: Cap your carb intake at 50 grams per day or less. 
• Protein: A moderate protein intake, ranging between 0.8-to-1 gram per pound of body weight daily, serves most people well. This is enough to maximize muscle growth; eating more won’t help you bulk up faster. That said, consuming more (1.5-to-2 grams per pound) while bulking may help minimize fat gain.
• Fat: Get the remainder of your calories from fat. 

3. Eat easily digestible foods. 

Choosing easily digestible foods can make it more straightforward to meet your calorie goal. Eating fatty cuts of meat, fatty fish, and whole eggs can help, as can incorporating nutrient-dense, calorie-rich condiments like avocado and olive oil. 

Prioritizing these foods gives your body the calories it needs to build muscle without the bloated feeling of overeating.

4. Lift weight 3-to-5 times weekly. 

Do 3-to-5 strength training workouts per week that focus on the following:

• Compound exercises: Compound exercises allow you to lift heavy weights safely, making them ideal for gaining size and strength in all your major muscle groups. 
• Heavy weightlifting: Training with 75-to-85% of your one-rep max (weights that you can do 6-to-12 reps with before failing) helps you build more muscle than training with lighter weights. 
• Progressive overload: Strive to add weight or reps to every exercise in every workout. This is known as progressive overload, and it’s the single most important driver of muscle growth.

If you want a training program that involve all of the above, check out my fitness books for men and women, Bigger Leaner Stronger or Thinner Leaner Stronger.

5. Take the right supplements. 

You don’t need supplements to gain muscle and strength, but the right ones can help.

The best supplements for building muscle are:

• Protein powder: Taking protein powder is a convenient way to provide your body with the nutrients needed to build muscle tissue and recover from workouts. If you want a clean and delicious protein powder, try Whey+ or Casein+.
• Creatine: Creatine boosts muscle and strength gain, improves anaerobic endurance, and reduces muscle damage and soreness from your workouts. If you want a natural source of creatine that also includes two other ingredients to enhance muscle growth and improve recovery, try Recharge.
• Pre-workout: A quality pre-workout helps you train harder by enhancing energy, mood, and focus, increasing strength and endurance, and reducing fatigue. These benefits are particularly advantageous if you’re new to keto and struggling to train because of “keto flu.” If you want a natural pre-workout containing clinically effective doses of 6 science-backed ingredients, try Pulse with caffeine or without.

(And if you’d like even more specific advice about which supplements you should take to reach your health and fitness goals, take the Legion Supplement Finder Quiz. In less than a minute, you’ll know exactly what supplements are right for you. Click here to check it out.)