Bodybuilding While on the Ketogenic Diet

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We commonly associate carbohydrates with performance in the gym and muscle growth.

After all, carbs are the main source of fuel for the body. Without it, we’d be doomed to walk around tired, small, and weak.

Or would we?

The truth is, carbs play a very small role in building an amazing body (or simply improving your body composition). Most people obsess over the macronutrient as if it’s the main determinant.

“Should I be eating 250 grams of carbs or 275?”

“Should I eat 45 grams of carbs before workout and 45 after or eat 70 before and 20 after? AGH, I’m going crazy!”

Sure, optimizing your meal timing can give you a slight edge, but don’t expect radical improvements. If you truly want to build muscle and lose fat effectively, there are other important things that you need to pay attention to regardless of what diet you’re following.

The Five Factors That Affect Muscle Growth and Fat Loss

The fitness industry may be lacking some things, but silly concepts, dumb training schemes, and useless supplements don’t fall into that category.

It won’t take you long to find someone who’s selling snake oil.

But the four factors that we’ll briefly discuss are what’s going to give you the most bang for your buck. They will be responsible for most of the progress you’ll make.

Eat enough calories and protein.

If you want to lose fat, you need a sensible caloric deficit. If you want to build muscle, you need a small caloric surplus. In both cases, you need enough protein to build, repair, and grow muscle mass.

Apply yourself in the gym.

There needs to be a fine balance between training hard and training smart in the gym.

Recover well.

Sleeping at least 7 hours every night as well as structuring your training properly, so it allows adequate recovery are both very important for long-term progress in the gym.

Related: The Effects of Sleep on Muscle Growth and Fat Loss

Stay hydrated.

We can’t discount the importance of proper hydration. After all, the human body is roughly 60% water.

Wait, Weren’t We Discussing the Keto Diet?

Yes, we are.

I just wanted us to be on the same page. I don’t want you to think that a certain diet is going to out-do everything else.

Before we continue, a few words on the Keto diet:

As you may or may not know, the goal of the Keto diet is to push you into a state of ketosis. This happens when you eliminate almost all of the carbs from your diet, and your body’s glycogen stores get depleted.

At that point, your body has to switch gears and find a new energy source. This is where ketones come in.

In simple terms, ketones are byproducts of your body breaking down fats for energy.

And because your body is used to relying on carbs for energy, it’s going to need some time to adjust to the new energy currency. You’ll likely experience some low energy, mental fogginess, dizziness, and sugar cravings in the first few days.

Your workouts are also not going to be the best, but that will pass.

The Keto Diet and Fat Loss

We know that to lose fat efficiently, three things need to happen over an extended period:

  • We need to create a caloric deficit, thereby pushing the body to start using our fat stores to make up for the lack of energy coming from food.
  • We need to eat enough protein to support muscle repair, maintenance, and even further growth.
  • We need to provide our muscles with a stimulus and signal our body that, “Hey, we need that muscle mass. Don’t burn it for energy!”, most effectively done by lifting weights.(As a small side note, this is why exclusively relying on cardio for fat loss often makes people skinny-fat in the end. That’s because they end up burning a good chunk of their muscle mass, alongside the fat. But that’s another topic for another time.)

Now, how does the Keto diet come into play here? Let’s see:

The Keto diet is excellent at creating a calorie deficit.

Once you eliminate carb-rich foods from your diet and increase your intake of meat, fish, eggs, and green veggies, you’ll feel full on fewer calories.

That’s because both fiber and protein are highly satiating (1, 2). This could partially be explained because protein takes longer for the body to break down and high-fiber foods are often high in volume.

A big bowl of mixed greens can be as little as 150-200 calories while filling your stomach completely and satiating you.

The Keto diet allows you to eat enough protein, even more than is needed in some cases.

Think of it this way:

Say, for example, that you need to eat 2500 calories/day to lose fat at a rate of 0.5-1% of body weight per week, but you’ve eliminated carb foods from your menu.

To get enough protein and the 2500 calories, you can eat a lot of eggs, dairy, green veggies, meats, fish, etc.

The general recommendations given by most authorities out there are to eat between 0.8 and 1.3 grams of protein per pound of body weight.

If you are very overweight or obese, you can eat as little as 0.5-0.6 grams per pound.

(It wouldn’t make sense to eat 260 grams of protein every day if your lean body mass is nowhere near that.)

Now, by eating enough protein, you are also taking advantage of one neat trick of your body: Gluconeogenesis.

Put in simple terms; your body will be able to break down some of the protein into glucose (referred to as glucogenic amino acids) for energy.

The Ketogenic diet won’t impair your ability to lift weights.

While you’re still adapting to the lack of carbs, you probably won’t be able to train with the same intensity as before, but as we discussed, that period will pass in a few days to a week.

You’ll be weaker and less endurant during that adjustment period. After that, you’ll be able to effectively use ketones, glycerol (from fats), and glucogenic amino acids for energy.

This is a good time to increase the weights you’re lifting and reduce the total repetitions you’re doing. You’ll be able to provide an adequate stimulus to your muscles, signaling your body to spare them.

The Keto Diet and Muscle Growth

We’ve learned a good deal about the keto diet, but how does it relate to muscle growth? Well, to build muscle mass effectively, you need to:

  • Overload your muscles on a consistent basis through more sets, more repetitions, more weight on the bar, etc.
  • Provide your muscles with adequate volume. You can maintain your muscle mass with very few sets (with or without a caloric deficit). But to build muscle mass, you need to do at least ten sets per muscle group every week. Some individuals might need as many as 20 for muscle groups like the chest, back, and legs.
  • Adequate protein intake.
  • A small caloric surplus. The only exception being beginners, previously trained people who have taken a break from the gym, and steroid users.

In the fat loss section, we learned that the human body is an incredible machine that can adapt to numerous circumstances. In the case of keto dieting, it can switch gears and find new sources of energy.

With that said, there is no reason to assume that, past the adapting period, you will have any performance issues if you don’t consume any carbohydrates. The ketones, glycerol (from fats), and glucogenic amino acids (from protein) will provide you with the energy.

Whether you’re on the Keto diet or not, you need a small caloric surplus to facilitate muscle growth. Just as you cannot build a house without building blocks, your body cannot synthesize new muscle without having enough energy (calories) and building blocks (amino acids).

There is one drawback to bulking on Keto diet, specifically for individuals who have poor appetite, to begin with (also known as hardgainers).

Since a lot of the foods on the Keto diet are quite satiating, these guys and gals might have trouble eating enough food to create a caloric surplus. Some force-feeding might be needed.

On the other hand, the Keto diet is a great option for people with big appetites who always get fat while bulking. The improved satiety could help them eat just enough calories to gain weight slowly.

And finally, just like for fat loss, you need adequate protein intake to build muscle. But, as we discussed, eating enough protein on the Keto diet is a very simple task, because a majority of the foods will have moderate to high amounts of the macronutrient.


All in all, the Keto diet can be used to build muscle or lose fat effectively, and if you’re someone interested, don’t hesitate, try it.

And if you’re someone who chronically struggles with hunger (both during fat loss and muscle-gaining periods) on a high-carb diet, Keto could be your answer.

Follow me / Pump Some Iron on Instagram for updates @pump.some.iron

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Hey, I'm Brian, the creator of I've been weightlifting / bodybuilding for 20 years and now I'm ready to share some knowledge. Check out my About Me page to hear my story.

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