Can you Build Muscle Without Carbs?

Need carbs to build and maintain muscle? Not necessarily!

Some bodybuilders are moving away from traditional carb-heavy bulking and experimenting with higher-fat diets. That's right.

Antonie Bartels, the founder of Keto Fit, is one example of someone who has experienced changes in muscle mass and body composition while following a ketogenic diet. He's crazy about health and bodybuilding and shared his keto journey with us.

We asked him to share his experience and break down three reasons why a ketogenic diet might be an option for building muscle while managing body fat. We'll also look at what the research says.

Ketones and muscle preservation

The theory goes that you cannot maintain muscle mass without a high-protein intake. In reality, adequate protein intake remains important for maintaining and building muscle, regardless of whether you follow a ketogenic diet. Ketone bodies, especially beta-hydroxybutyrate (BHB), have been studied for their potential effects on muscle metabolism, but there is not enough evidence to conclude that ketosis itself prevents muscle breakdown.

When you’re following a ketogenic diet, your body increases its use of fat and ketones as fuel. This changes how your body uses energy, but maintaining muscle mass still depends on factors such as adequate protein intake, sufficient calories and regular resistance training.

Some studies comparing low-carb diets with higher-carb diets have found reductions in body fat while maintaining muscle mass. However, results vary depending on calorie intake, protein intake, training and the participants involved.

For example, a 2025 systematic review and meta-analysis found that ketogenic diets increased fat oxidation and reduced fat mass compared with other diets, without significant overall differences in muscle mass or strength. This suggests that a ketogenic diet can be compatible with maintaining muscle and strength, although it is not necessarily superior to other approaches.

Gain while staying lean 

A ketogenic diet encourages your body to use more fat as fuel. In the absence of sufficient dietary carbohydrates, your body increases its reliance on fat and ketones for energy. However, burning more fat for fuel does not automatically mean losing body fat. Fat loss still depends largely on your overall energy balance. A ketogenic diet can be one way to manage body composition, but it isn't the only approach.

Most people probably know the terms bulking and cutting. But I disagree with that traditional way of training and eating. While bulking, some people overeat. And yes, this can increase your weight and muscle, but it can also lead to unwanted fat gain.

The downside of this approach is that afterwards, you may need to start cutting for a longer period of time. During this period your body is in a caloric deficit, and without adequate protein and resistance training, you may lose muscle mass and experience a decline in performance.

Improve performance

I experienced that my performance went up after my body became fat-adapted. Before I began my ketogenic journey, my body wouldn’t handle carbohydrates very well and my energy levels would go up and down all day.

Especially in the morning, I didn’t have that much energy and after a big meal, it would feel like my body preferred to crash on the couch. Ever since I became fat-adapted, I've felt more comfortable relying on fat as a source of energy.

Let's say you're a well-trained athlete weighing 80 kg with a body fat percentage of 6%. This means you have approximately 4.8 kg of body fat. At roughly 9 calories per gram of fat, that's a substantial amount of stored energy. However, having stored fat available doesn't mean your body can use it quickly enough to fuel every type of exercise, particularly high-intensity efforts.

There is also research exploring this. In a study published in 2020, a group of 25 resistance-trained men was divided into two groups. One group followed a ketogenic diet and the other a traditional Western diet.

During the study, the ketogenic diet group saw an average decrease of 2.2 kg of fat and the Western diet group a decrease of 1.5 kg. Strength and power increased to a similar extent in both groups. These findings suggest that resistance training performance can be maintained or improved on a ketogenic diet, although results from one small study cannot be generalised to everyone.

More recent research also suggests that carbohydrates aren't always essential for strength training performance, particularly during shorter, lower-volume sessions. However, higher carbohydrate availability may benefit longer or more demanding workouts. Individual responses can vary.

Antonie's progress in only about a month

Bottomline

Contrary to popular belief, high-carb consumption is not essential to maintain and build muscle. This is possible on a ketogenic diet as well. However, keto is not necessarily better for muscle growth than other diets, and it isn't for everyone. Of course, muscle growth won’t come by itself, so you still have to keep challenging yourself in the gym and make sure you're getting enough calories and protein.

Research on ketogenic diets and factors such as testosterone levels and muscle protein synthesis is still developing. Current evidence does not establish that keto reliably improves these outcomes compared with other diets.

Now that you know that you don't necessarily need to bulk on carbs, here are 4 steps you can take to build and maintain muscle mass on keto:

Eat a caloric surplus

Consume more calories than your body burns daily. To gain mass, a modest surplus of around 150–500 extra kcal per day can be a starting point, depending on your needs, training experience and goals. These extra calories can come from fats and proteins. They don't necessarily have to come from carbs.

Eat your proteins

Make sure you're eating enough protein to build muscle. For people doing regular strength training, around 1.4–2.0 g of protein per kg of body weight per day is a commonly recommended range, although individual needs can vary. Adequate protein is important whether you follow keto or a higher-carb diet.

Do regular strength training

For muscle growth to happen, you have to create stress in your muscles that is different from what your body is already used to. This can be done by exercising regularly and progressively increasing the challenge through your weights, repetitions or training volume. If you're struggling to get motivated to workout, make sure to follow these extra tips. 

Don't forget the electrolytes

Maintaining proper electrolyte levels is important for normal muscle and nerve function. These include sodium, potassium and magnesium. Electrolytes are lost through urine and sweat, and changes in fluid and sodium balance can occur when starting a ketogenic diet. Inadequate electrolyte intake can contribute to symptoms such as fatigue or muscle cramps. This is an electrolyte drink recipe that you can try out. There's no need to supplement electrolytes unnecessarily, so consider your individual needs.

Still in doubt? Keto can be an option worth exploring, but the best approach is the one that suits your goals, training and lifestyle.

 

If you're looking for a chocolate snack to enjoy around your workouts, our Funky Fat chocolate bars are made with carefully selected ingredients, MCT oil powder from coconuts and no added sugar. You don't have to follow keto to enjoy them.

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