It's possible, but it's not easy. Here, everything you need to know about keto bodybuilding.

By Gabrielle Kassel
keto bodybuilding diet meal of eggs
Credit: istetiana/Getty Images

If there's one thing the keto diet and bodybuilding have in common, it's that both require admirable levels of discipline. So it shouldn't be too surprising that there's a new wave of bodybuilders who are using the low-carb, high-fat lifestyle to build muscle without carbohydrates.

By now, we know that eating fat doesn't make you gain fat. Still, the idea of following a fat-dominant diet (cheese! bacon! avocado!) while competing in a sport known for sculpting shredded, muscle-popping bodies is...counterintuitive, to say the least. (Related: Is the Keto Diet Bad for You?)

"The ketogenic diet is basically the complete opposite of traditional bodybuilding diets," says Jose Vallejo R.D., a Miami-based certified personal trainer and sports nutritionist.

Need a refresher? The ~typical~ bodybuilding diet is high in protein and carbohydrates and low in fat. "It typically consists of 55 to 60 percent of your calories coming from carbohydrates, 30 to 35 percent protein, and 15 to 20 percent fat," says Vallejo. On the flip side, the keto diets basically take carbs out of the equation by calling for 75 percent of your calories from fat, 20 percent from protein, and only 5 percent from carbs.

Still, experts say it is possible to pull off keto bodybuilding. "There's a common misconception that you need a carbohydrate-heavy diet to build the muscle wanted in bodybuilding, but that's far from the truth," says Vallejo. In fact, he says a lower-carb, higher-fat may actually be beneficial. (Here: One Bodybuilder Shares What It Takes to Be a Champion).

So, what does a keto bodybuilding diet even look like?? Here, Vallejo and other nutrition and bodybuilding experts share how bodybuilders can make a ketogenic diet fit their needs and even help them perform better.

Understanding the Goals of Bodybuilding

Whether you're interested in taking the stage as a #fatpowered athlete, or are just curious about how keto and bodybuilding can exist together, first you need to understand the goal of bodybuilding. To put it simply: lose fat and put on the same time. (Related: The Complete Guide to Burning Fat and Building Muscle).

There are a few different categories of bodybuilding, which dictate how shredded you need/want to be when strutting across the stage. But whether you're competing in bikini, figure, physique, or bodybuilding, the same muscle and fat principle stands. (See more here: The Beginner's Guide to Bodybuilding)

In order to do these two things, competitors usually split their season into two phases, explains Vallejo. During the bulking phase, athletes work to boost strength and muscle mass, and during the cutting phase, they emphasize fat loss and looking ~cut~. The biggest difference between these two phases is calorie consumption, he says. "You might be eating 3,000 to 4,000 calories for a couple of months so that you're in a calorie surplus and bulking, and then go down to 1,500 to 2,000 so that you're in a calorie deficit leading up to when you're going to take the stage," he explains.

Friendly PSA: Severely cutting calories and/or rapidly dropping weight can be dangerous and bad for your long-term health, says Monica Auslander Moreno, M.S., R.D., L.D.N., a nutrition consultant for RSP Nutrition. "And it isn't advisable for folks who have a history of disordered eating." (See: Why You Should Consider Ditching Restrictive Dieting).

Most bodybuilders work with a coach and/or sports nutritionist who help them safely calculate their caloric and macronutrient needs throughout the training season. (Related: Three Experts Share How To Healthily Cut Calories).

How Keto Bodybuilding Works

When you're eating a non-ketogenic diet, your body runs on the energy it gets from glucose, which is found in carbohydrates. Keto forces your body to use a completely different energy source called ketones, explains Justin Casipi, a NASM-certified personal trainer and former bodybuilder with Fitness Formula Clubs.

"When there's no glucose for the body to use as energy, your body goes into something called 'ketosis' which is when you're predominantly using fat as fuel," he explains. Yup, you're literally using your own fat stores as energy. (See more: Everything You Should Know About the Ketogenic Diet).

The potential benefits of this: weight and fat loss, steady energy, and reduced cravings, says Douglas Smith, a bodybuilder and founder and CEO of True Nutrition protein powder. Understandably, these benefits might be appealing to someone who hopes to walk on stage with as little body fat as possible.

And science says it works. "Research confirms that the combination of a strength training regimen and ketogenic diet can help folks increase lean muscle mass without the excess weight gain, explains Vallejo. (Want visual proof? Check Out One Woman's Results from Trying the Keto Diet.)

"Some bodybuilders also choose a ketogenic diet for its purported health benefits, not just because it might help them reach their bodybuilding goals," says Smith. (Though, initial research suggests that the keto diet may not be healthy in the long run.).

One warning: Your strength might suffer quite a bit at the beginning. Your body uses glucose (from carbs) as an important energy source during workouts, so when you drastically reduce your carb intake, your body has less easy-access fuel for your training. As a result, workouts may feel more difficult. "When you're in the beginning phases of the keto diet, your body is switching from breaking down glucose for energy to breaking down fat," explains Vallejo. "Since your body is used to burning glucose (from carbs) as its main source of energy your entire life, it needs time to adjust." Good news: Vallejo says that once your body is fat-adapted, your fitness levels should return. (Related: 8 Things You Need to Know About Exercising on The Keto Diet)

Now that you know it's possible (and even beneficial!) to practice keto while bodybuilding, let's take a closer look at what a keto bodybuilding diet might entail. Ready?

Learning Your Keto-Friendly Macros

There are three main variations of the basic keto diet that a bodybuilder may choose to follow: cyclical ketogenic diet (CKD), targeted ketogenic diet (TKD), or a high-protein, modified ketogenic diet. All three iterations are high-fat, low- to moderate-protein, and low-carb, says Justin Casipit a former bodybuilder and NASM-certified personal trainer with Fitness Formula Clubs in Illinois. More each below.

Cyclical ketogenic diet (CKD): Also known as "carb cycling", this eating plan was used in bodybuilding for fat loss long before it became classified as a variation of keto. "This type of diet involves consecutive low carbohydrate (keto) days followed by carefully planned refeed days that are high-carb and low-fat," explains Casipit. The goal of planned refeeds is to restore glycogen levels. "The idea is that this allows the athlete to maintain their training intensity while also taking advantage of the fat-loss benefits of keto." (See More: What is Carb Cycling, and Should You Try It?)

Targeted ketogenic diet (TKD): The targeted ketogenic diet is basically love-child of carb cycling and nutrient timing. "It allows you to eat some carbs, but only right around your training sessions," explains Casipit. That means focusing your carb consumption right before and during your workout. The point? To give the body enough glucose to fuel your workouts and keep the intensity up, while taking advantage of the ketogenic state for fat loss during the remainder of the day/night. Note: this takes a lot (like, a lot a lot) of planning, prepping, and tracking to do successfully.

High-protein or modified ketogenic diet: This is similar to the basic ketogenic diet consisting of high fat and low carb, however, due to the goals and increased protein demands of athletes (especially in bodybuilding) the diet is modified to have a greater percentage of calories from protein, explains Casipit. On this diet, you might get 65 percent of your calories from fat, 30 percent from protein, and 5 percent from carbs.

All three of these keto variations will require a slightly different macronutrient breakdown. That said, "most keto bodybuilders still try to keep net carbohydrates lower than 20g per day while keeping fat intake at around 70 percent of their total calorie intake," says Logan Delgado, a keto coach and keto-bodybuilding athlete. There are many factors go into this ratio including body weight, age, sex, the intensity of your workouts, and where you are at in your season.

Sound complicated? TBH, it kind of is. That's why if you think keto bodybuilding might be for you, Vallejo recommends working with an expert to find these numbers. This expert can also help make the diet feel manageable.

"In my opinion, the biggest downside of keto bodybuilding is that you have to follow a rather rigid breakdown of fat, protein, and carbs for the keto diet to work," says Vallejo. "So you might not be able to enjoy or eat exactly what your family or friends eat." This can produce unwanted stress and be downright mentally draining, he explains. And nothing thwarts weight loss efforts quite like stress. (Related: The Surprising Way Stress Makes You Gain Weight).

Counting Your Calories

"Whatever eating plan you're following for bodybuilding, the number of calories you're consuming during the cut and bulk matter," says Casipit. He recommends using an online calculator to figure out how many calories you need throughout your season. (For more info on how to calculate your caloric needs, check out this Guide to Vegan Bodybuilding—yes, that's a thing, too!—where a doc explains in detail how to find your caloric needs).

Or you can get your basal metabolic rate tested, and then adjust that number for a deficit or surplus, he says. (FYI: It'll cost you a little cash.)

During bulking season, Casipit emphasizes the importance of maintaining that caloric surplus… even if you feel stuffed. "Some ketogenic dieters report feeling really full due to the high satiating levels of fats and protein." Still, he says, in order for keto to be effective during bulking season, that surplus is important.

On the flip side, "fat gives off major satiety signals within the body which is a major bonus when you're in a cutting phase," says Smith.

Just remember: While calorie counting is an essential part of bodybuilding, the practice of calorie counting is tricky territory, especially for folks with a history of disordered eating. That's why even some nutritionists like Moreno say you should opt out.

Keeping Your Keto Clean

There's a term for keto diets that favor foods like bacon, cheese, and packaged foods—which may fit keto rules, but aren't clean. It's called dirty keto. This isn't optimal for bodybuilders, says Smith, because while you may still lose weight, you need a nutrient-rich diet to train your best. (See more: Nutritional Deficiency Could Be Ruining Your Workout).

Instead, to do bodybuilding keto the right way, every meal should include a lean protein or grass-fed meat, a non-starchy vegetable and fruit, a healthy fat (like nuts, seeds, or oils), and sometimes a lower-glycemic carbohydrate (like rice or sweet potato). (Related: Why One Dietitian Hates the Keto Diet)

Add some of these keto-approved foods, courtesy of Casipit, to your grocery list. (See more: The Beginner's Guide to Bodybuilding Meal Prep and Nutrition).

Nuts and seeds: Cashews, macadamia nuts, pumpkin seeds.

Vegetables: Avocados, spinach, and other greens, broccoli, asparagus, cabbage, mushrooms, bell pepper.

Fruits: Blackberries, raspberries, and blueberries. (You'll want to measure these out to keep track of their carbohydrate content.)

Animal-protein: Chicken thighs and legs, bacon, whole eggs, full-fat cheese, beef, filet mignon, porterhouse, rib eye,

Fatty fish: Salmon, mackerel, sardines or anchovies.

Other: Pork rinds, olive oil, salted butter, sour cream, cream cheese, mayonnaise, and cheese. (Related: The Best Fats to Eat On the Keto Diet).

Hydrate, hydrate, hydrate

Clean keto dieting also prioritizes water consumption. When your body is shifting into keto, it loses a significant amount of fluid and electrolytes. Why? Because carbs retain water, less carbs=less water retention. While this is great for water-weight loss, "it's important to replace the H2O and electrolytes (sodium, potassium, magnesium, phosphorus, and calcium), because if they're depleted it's detrimental to training," says Smith. Plus, you'll feel less than great. Helllloketo flu! (Related: 3 Signs You're Dehydrated During Your Workout)

Symptoms of electrolyte imbalance include fatigue, lethargy, nausea, headaches, and irregular heartbeat. Don't worry, this is totally temporary, says Casipit. "Just be sure to hydrate and replace electrolytes in this period."

A Day of Eating On a Keto Bodybuilding Diet

To reiterate this important PSA: Everyone's caloric and macronutrient needs are going to be different! The below meal ideas from Casipit and Auslander may not work with your personal meal plan but they can serve as inspiration or a jumping-off point for keto bodybuilding.

Breakfast: Fry a few eggs with low-glycemic veggies like peppers, onions, mushrooms, spinach, and herbs with a side salad OR (if you have egg fatigue) sauté 1 ounce of sugar-free sausage and 1 cup bell pepper with 1 tablespoon of olive oil, and then top with pepper jack cheese. (Or, if you're in a rush try one of these keto protein bars).

Lunch: Make a lettuce wrap by coating a giant piece of romaine with 2 tablespoons mayonnaise then roll with 2 ounces grilled chicken, 6 pieces of bacon, a handful of small cherry tomatoes, and some cheese OR have a bun-less cheeseburger with a side salad.

Dinner: Bake 4 ounces of salmon and serve with 3/4 cup mashed cauliflower topped with 1 tablespoon of butter, 2 tablespoons of sour cream, some sour cream, cheese, bacon bits OR make homemade chicken noodle soup with bone broth, organic chicken thighs, organic coconut oil, kale, carrots, and onions. (For dessert, why not try this genius keto Nutella recipe?)

The Takeaway On Keto Bodybuilding

"Why you'd choose to be on a keto diet versus any other bodybuilding diet comes down to your individual goals and preferences, but, done right, any of them can get you from point A to point B," says Smith. "Some people swear by going keto, others don't like it that much. If you're curious, your best bet is just to try it."

Just remember that careful planning is crucial if you want to look and feel good on a keto bodybuilding diet. Chat with a nutritionist if you want to give it a try.