Nutrition

How To Build Muscle On A Keto Diet

The keto (or ketogenic) diet is fast becoming one of the most popular dietary approaches in the world. 

While many will use it to help manage their weight, it may also be of benefit to those looking to build more muscle. 

In this article we’re going to cover what exactly the keto diet is, misconceptions regarding keto and muscle building and how the keto diet can actually help us to build muscle. 

 

What is the keto diet?

The keto diet is a highfat, lowcarbohydrate diet thats often accompanied by increased protein intake. 

It was originally created to help reduce the severity and frequency of seizures for those who suffer with epilepsy. More recently it has been implicated as a viable weightloss diet and may be of benefit to those with metabolic conditions too. 

The keto diet is focused around the goal of achieving ketosis and minimising insulin production. Ketosis is the state in which we are so carb depleted that our body will use dietary fat and or fat stores for energy.  

The body breaks down fat to produce ketones (hence ketosis) which can enter the energy cycles to produce energy. It typically takes around 34 days of a very low carb diet (sub 50g a day) to achieve ketosis.1 For some it can take as much as a week!  

This is arguably the toughest hurdle for first time keto-dieters to overcome as this period of metabolic adaptation can be stressful, met with cravings and hunger, fatigue and extreme irritability.  

Theres also a chance of developing what is known as the “keto flu” – flulike symptoms that occur during the metabolic adaptation stage.2 

Swapping in tasty, low-carb snacks can certainly help with the transition to a keto diet and some of our keto friendly snack favourites include nutsnut butterprotein bars and protein bites! 

 

Misconceptions regarding keto and muscle building

The main reason why people are sceptical about building muscle following a keto diet is due to its effect on insulin production. 

Insulin is described as an anabolic hormone (i.e. a hormone associated with “creating or building” rather than breaking down).3  

It does this by binding to a cell (such as a muscle cell) and signals to that cell to take in nutrients. Relating back to muscle building, the influx of nutrients can contribute to repair and growth of the muscle (after having been broken down by exercise). 

Whilst this may be true, there are other more important pathways to support muscle building. Highprotein diets rich in highquality proteins (either animal sources or complimentary plant sources) will contain plenty of leucine.  

Leucine is one of the building blocks of protein (an amino acid) which is most popular for its ability to stimulate muscle protein synthesis. 

 

How would a keto diet support muscle building

As mentioned, keto diets will typically be higher in protein and protein sources, especially leucine rich sources, that can stimulate muscle protein synthesis on their own.4 Howeverinsulin may have an added benefit when it comes to hypertrophy (growth). 

One important thing to note though, if met with this argument, is that leucine itself also actually stimulates insulin production.4 

So, the necessity for carbohydrate really comes into question then. This isnt to say it may be optimal for some when it comes to recovery and adaptation, but what it does suggest is that the thought you cannot build muscle on a keto diet appears to be incorrect (which is reflected in a large number of studies supporting ketogenic diets and muscle building).5 

Whilst not directly related to muscle building per se, the keto diet may also help you get leaner (which contributes to a more defined muscular look) and retain more muscle mass (especially true when it comes to age related loss of muscle mass or inactivity).5 

Notably, as you undergo metabolic adaptation to a ketogenic diet you may experience a decrease in exercise performance (just as you would expect if you were feeling “under the weather”). 6 

However even this appears to even out over time (although individual response varies and some people perform better on a low carb diet and some perform better on a high carb diet).7  

Muscle may also appear “smaller” or “flat” due to a reduction in glycogen and water, but the actual tangible muscle hasn’t changed. 

 

Take home message

The thought that a keto diet can negatively impact your ability to gain muscle is misleading and shows a lack of understanding as to how muscle building works. 

Muscle building is just as achievable following a ketogenic approach as it would be any other and may arguably be greater than others if promoting an increased intake of high-quality protein sources. 

Yes, there may be some initial difficulty when transitioning over, but there appears to be no reason as to why you candevelop a significant amount of muscle following a ketogenic diet. 

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.


1. Scott, J. M., & Deuster, P. A. (2017). Ketones and Human PerformanceJournal of special operations medicine: a peer reviewed journal for SOF medical professionals17(2), 112-116.

2. Bostock, E., Kirkby, K. C., Taylor, B. V., & Hawrelak, J. A. (2020). Consumer reports of “Keto Flu” associated with the ketogenic dietFrontiers in Nutrition7, 20.

3. Dimitriadis, G., Mitrou, P., Lambadiari, V., Maratou, E., & Raptis, S. A. (2011). Insulin effects in muscle and adipose tissueDiabetes research and clinical practice93, S52-S59.

4. Figueiredo, V. C., & Cameron-Smith, D. (2013). Is carbohydrate needed to further stimulate muscle protein synthesis/hypertrophy following resistance exercise?Journal of the International Society of Sports Nutrition10(1), 1-3.

5. Paoli, A., Cancellara, P., Pompei, P., & Moro, T. (2019). Ketogenic diet and skeletal muscle hypertrophy: a frenemy relationship?Journal of human kinetics68(1), 233-247.

6. Sherrier, M., & Li, H. (2019). The impact of keto-adaptation on exercise performance and the role of metabolic-regulating cytokinesThe American journal of clinical nutrition110(3), 562-573.

7. Brinkworth, G. D., Noakes, M., Clifton, P. M., & Buckley, J. D. (2009). Effects of a low carbohydrate weight loss diet on exercise capacity and tolerance in obese subjectsObesity17(10), 1916-1923.



Jamie Wright

Jamie Wright

Writer and expert


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