Keto Exercise Part 2: Building Strength On Keto

Living a healthy Keto lifestyle isn’t just about cutting carbs and eating fat. It’s also about maintaining strength and muscle. 

As we age, muscle keeps us fit and functional. And not only does muscle mass look good, but it’s also a predictor of longevity.[*]

But many people worry that it’s difficult (if not impossible) to build strength on a Keto diet. Don’t you need carbs to build muscle?

Actually, no. While carbs have anabolic (growth) properties, a protein-sufficient Keto diet is perfectly compatible with strength gains.[*]

In this second installment of our Keto exercise series, we’ll explore how to successfully build strength and muscle on Keto. Let’s dive in, shall we?

Protein and Resistance Training

To maintain strength and muscle, there are two non-negotiables:

1. Adequate protein intake
2. Resistance training 

If you want to gain muscle, add a third item to that list: A caloric surplus.[*]

A quick primer on protein. Protein is made of amino acids, building blocks of most human tissues, including muscle tissue. 

The amino acids most important for muscle building are the branched-chain amino acids (BCAAs) leucine, isoleucine, and valine. Of the three, leucine is the king for signaling muscle growth and repair—also known as muscle protein synthesis.[*]

Leucine is found in meat, whey, and eggs—and helps you maintain positive net protein balance in muscle tissue. Positive net protein balance means that protein synthesis outcompetes protein degradation. Or put more simply: That muscle growth wins over muscle breakdown. 

Lifting weights kicks off this process by breaking down your muscle tissue. Then your muscles—fueled by protein—adapt by growing back bigger and stronger. 

So, how much protein do you need to complement Keto strength training? Read on. 

How Much Protein On Keto?

The current RDA for protein is 0.8 grams per kilogram of body weight, or about 50 grams of protein per day for a 140-pound person.  

But according to an analysis in the journal Food & Function, the RDA is insufficient to support strength and muscle gains during physical activity.[*] For instance, a highly-active 140-pound person needs double that amount, or 100 grams of protein per day. 

That’s a significant amount of protein, and many people on Keto are falling short. Why? In part, because there’s confusion about fat, protein, and carbs (macros) on Keto. Some explanation will help.  

A modified Ketogenic diet is high in fat, moderate to high in protein, and very low in carbs. By calories, it’s about 60% fat, 30% protein, and less than 10% carbohydrate.[*]

But here’s what many people forget: A gram of fat contains 9 calories, while a gram of protein or carbohydrate contains only 4 calories. 

Fat is over twice as energy dense as protein! This means that, by mass, you should be eating more protein than fat on a 60/30/10 Keto diet. Keep that in mind when structuring your low-carb meals. 

Will Protein Kick You Out of Ketosis?

Let’s see what the research says. In one study, researchers fed seventeen obese men two diets at different times[*]:

1. Non Keto (high protein, moderate carb)
2. High protein Keto (high protein, low carb)

What happened? On the high protein Keto diet, the men not only lost more weight, but they also maintained nutritional ketosis. 

So yes, higher protein intakes are concordant with Keto’s metabolic benefits. And they’re essential for keeping muscle on your frame. 

Do You Need Carbs To Build Muscle?

Conventional wisdom holds that you need carbs to build muscle.  

The logic is simple. Eating carbs raises levels of insulin, an anabolic hormone—which in turn brings more amino acids (protein) into skeletal muscle. More insulin, more gains. 

If your goal is to pile on maximum muscle, carbs may help—provided you’re eating enough protein and training the right way. But if your goal is to lose body fat as you maintain lean mass, Keto is the way to go. 

Put another way: though carbohydrate-containing diets appear to be the better option for muscle and strength gains, a few studies suggest that some people can achieve these gains on Keto.

In one study, overweight people on very low-carb diets had similar strength gains to higher-carb controls after a resistance training program.[*] The difference was: The Keto folks lost more fat. 

Another study was even more interesting. Twenty-six men were split into two groups— very-low-carb and high-carb—then put on an 11-week strength training program. Protein was held constant between the groups.[*]

But even with equal protein and more carbs, the high-carb group lost less body fat and gained less muscle than the Keto group. Same training, same protein, fewer gains.  

How Keto Preserves Muscle

Keto has properties that may explain how folks (in multiple studies) have succeeded in adding strength and power—while preserving muscle—without carbs.

Consider the following:

• Beta-hydroxybutryate (BHB)—the main energy ketone—interacts with leucine to promote muscle protein synthesis and prevent muscle breakdown.[*]
• Low carb diets are generally higher in protein (the crucial ingredient for muscle growth) than high-carb diets.[*]
• The Keto diet may increase adrenaline, which inhibits muscle breakdown.[*]
• A small study found that a Keto diet increased testosterone (an anabolic hormone) vs. a high-carb western diet.[*]
• Another study found that a Keto diet increased IGF-1 (another growth factor) in skeletal muscle vs. a high-carb western diet.[*]

This isn’t to say that Keto is the optimal muscle gains diet. If you really want to pack it on, you’d want to stimulate insulin—which is also a fat-storage hormone—by eating carbs along with your protein and strength training. Body builders, for instance, saw greater muscle gains on a high-carb diet vs. a Keto diet (only the high-carb group had statistically significant muscle gains)—although both groups had similar strength gains[*] 

But if pure muscle gains aren’t your #1 goal, you can certainly add or maintain muscle on a Keto diet. Just remember that you need a caloric surplus, plenty of protein, and a strength training program. Without these three elements, it will be difficult to gain lean mass on Keto. 

How To Build Strength On Keto

The formula for strength training on Keto isn’t complicated. Just eat enough protein, lift weights, and give your muscles time to recover between sessions. 

If you’re looking to gain muscle, bump up your fat and protein calories. Adding 10% more calories to your daily total is a good starting point, but you’ll want to experiment to see what works best for your body. 

As far as the weight training itself goes, you have plenty of options. If you’re looking to gain muscle, try a low-rep high-weight program. For muscle maintenance and endurance, look more to high-rep low-weight regimens. And for specific exercise ideas, check out our comprehensive Keto Exercise Guide. 

Finally, track all the crucial variables—protein, calories, body weight, and even exercise sessions —with the Carb Manager app. It will help you stay accountable, motivated, and dialed in as you get stronger on Keto.