Ketogenic Diets for Bulking

The ketogenic diet is nothing new. The high fat, low or no carbohydrate diet was first developed in the 1920s as a treatment for pediatric epilepsy. In recent history, the ketogenic diet has been used by the bodybuilding and strength training community as one of the most popular and controversial ways to improve body composition.

The diet was initially developed as an alternate means to fasting, which was found to induce the state of ketosis in the patient (1). Early physicians found not only a decreased frequency of epileptic seizures in patients who were in ketosis but also accelerated fatty acid oxidation, which then led to the loss of body fat. Ketosis is often referred to as the body’s “fat burning” mode (2). Some benefits often associated with ketogenic diet include:

• Reduction in body fat
• Appetite suppression
• Mood elevation and mental clarity (after the initial weaning period of 3-5 days)
• Stable blood glucose levels
• Reduced cardiovascular risk factors (chronically elevated insulin, triglycerides, etc.)
• Lowered cancer risk (cancer cells thrive on glucose)

So, what exactly is ketosis?

Ketosis (not to be confused with ketoacidosis in diabetic patients), occurs during a state of prolonged carbohydrate deficit, where the liver converts fatty acids into ketone bodies (acetoacetate, β-hydroxybutyrate, and acetone). Normally, ketone concentration in the blood is very low and is primarily regulated by insulin and glucagon (4). It may reach high levels during periods of accelerated fatty acid oxidation combined with low carbohydrate intake or impaired carbohydrate use. Glucose is the preferred fuel source for various tissues in the body, including the brain. However, with very little glucose present and ketone body formation increased, most cells in the body can use utilize ketone bodies as an alternate energy source. Whatever glucose requirements there are by the body can be easily met via gluconeogenesis (where glucose is produced from amino acids or the glycerol backbone formerly attached to fatty acids as a triglyceride).

Extensive variations of the ketogenic diet have been branded and marketed primarily for weight loss for decades, some with more or less rigidity than others, but all with the same underlying concepts. In recent years, ketogenic diets with a focus on mass gaining have been introduced, with mixed reviews.

Will I lose muscle?

Alright, so we know keto diets help with epilepsy and cause accelerated fat loss, but what about muscle? Aren’t dietary carbohydrates necessary to preserve if not build lean mass? Maybe not.

During the hormonal shift from burning glucose to ketone bodies, there is a reduction of circulating levels of insulin with a subsequent increase in circulating levels of glucagon. This makes sense as insulin is the storage hormone responsible for removing glucose from the blood and depositing it in target tissues. The most well-known action of insulin as it pertains to skeletal muscle is the uptake of glucose and amino acids. Stimulation of anabolic processes such as protein, glycogen, and fat synthesis follows. While insulin can be thought of as anabolic in nature, glucagon is catabolic. It is responsible for the release of glucose from stored glycogen and the stimulation of gluconeogenesis and fatty acid mobilization.

Despite the fact that anabolic actions are decreased and catabolic actions are increased, muscle protein breakdown is not accelerated as one might guess, and preservation of muscle mass has been shown in more than one study examining the effects of a very low carbohydrate diet. When people first embark on a ketogenic diet, they might “feel” like they’re losing muscle. This shift in muscle “fullness” is the result of muscle glycogen and total body fluid and electrolyte content and not the result of a loss of actual contractile tissue. Muscle preservation is made possible through various mechanisms. Low blood sugar stimulates adrenaline, which has been shown to directly inhibit proteolysis (protein breakdown) of skeletal muscle. Provided there is enough substrate present for oxidation (fatty acids and ketone bodies), oxidation of muscle amino acids for fuel is decreased.

It is also shown that certain ketone bodies can decrease leucine oxidation. We know leucine is key anabolic trigger for muscle protein synthesis, and an increase in its incorporation into skeletal muscle has been shown in subjects while on a very low carbohydrate diet. Low blood sugar stimulates growth hormone (GH), which we know to be a potent stimulator of muscle protein synthesis. Due to the preservation of amino acids, dietary protein availability has been shown to increase IGF-1 levels up to two-fold. Studies also report increases in skeletal muscle protein synthesis even though insulin levels are dramatically decreased.  These effects are shown primarily in a caloric deficit, and it can be inferred that increased protection against muscle loss would be seen in a caloric surplus.

The take-home point: to prevent muscle loss when cutting carbohydrates out of your diet, it is pertinent to make sure dietary protein levels are sufficient. One should also consider taking in enough dietary fat to ensure fatty acid and ketone body production is sufficient to offer these protective metabolic effects (7).

Effects on Strength Training and Performance

What about strength training? Will a ketogenic diet hinder progress in the gym, thereby limiting my overall growth potential? It depends on how you train.

While a few studies utilizing submaximal exercise indicate no significant decrease in strength performance in athletic populations (5, 9, 10), several others have shown that reduced muscle glycogen is been associated with muscle weakness (14), decreased force production and reduced strength (6, 11). Resistance training in a lower rep range (1-5 reps) for low total volume primarily utilizes the ATP-PC energy system and might not be as effected by ketogenic dieting and low muscle glycogen levels. Athletes performing resistance training programs using more total training volume, either by performing multiple lower rep sets and/or higher rep sets in the traditional “hypertrophy” rep range (6-12 reps) are at least partially dependent on muscle glycogen stores to provide fuel for their training (12, 13). If you train with any sort of volume and intensity in the gym, the amount of available muscle glycogen during these types of workouts appears to be related to the total work produced and duration of the strength training sessions, and in the absence of adequate muscle glycogen, it is likely a decrease in work capacity will be seen.

Carbs and keto, can they coexist?

Can I take advantage of a ketogenic diet while incorporating enough dietary carbohydrates to fuel my intense training sessions and take advantage of the crucial hormonal response to carbohydrates around the training time? Quite possibly, but it’s complicated.

In recent years, cycling dietary carbohydrate in and out of your otherwise low carbohydrate ketogenic diet have become popular as a way of achieving the benefits of the ketogenic diet along with the ability to maximize your training efforts and muscle hypertrophy response. Often called “Cyclic Ketogenic Diets” or CKD, they are used as a way of maintaining the ability to perform high volume and/or high intensity exercise during a maximal fat loss phase of one’s diet (utilizing a ketogenic approach). Cyclical “refeeds” or “carb-ups” restock muscle and liver glycogen, as well as upregulate various hormones and thyroid activity that may be depressed during prolonged low calorie and/or low carbohydrate dieting. These glycogen stores can later be used during strength training sessions to ensure adequate stimulation and performance (8).

While this might seem like an ideal way to have your cake and eat it, too (bad pun intended), this offers a few drawbacks. Refilling muscle and liver glycogen to maximum capacity may take 24 or more hours, and will probably take the athlete out of ketosis at least during the period when carbohydrates are consumed. To enter back into a ketogenic state, the athlete must then burn through said glycogen stores over a period of 3-5 days, thereby negating the beneficial effect of being in ketosis. If an athlete refeeds once every 5-7 days, the athlete will almost never get back into a state of ketosis, largely losing the potential benefits of the diet. A constant “yo-yo” effect of refilling and depleting glycogen can also take its toll physically and mentally on an athlete, including periods of decreased mood and mental performance, apathy, and lethargy.

The refeed process may also hinder fat oxidation (and may even contribute to fat accumulation) if overdone or combined with too much dietary fat during the time of the increased carbohydrate ingestion, especially if done during a period of caloric surplus (such as the offseason for a bodybuilder). It would be prudent for an athlete partaking in this practice to refeed judiciously and strive to balance out the quantity and duration of the refeed with the time it takes to enter back into ketosis.

Why bulk with keto?

While the research on this topic is sparse at best with regards to resistance trained athletes, it is hypothesized that one can stay in and experience the benefits of being in ketosis while still taking advantage of the hormonal milieu from consuming carbohydrates (and possibly proteins and amino acids) around a workout. Currently there are researchers looking into this phenomenon, and the secret may lie in the amount and timing of carbohydrates consumed.

A variation of the cyclic ketogenic diet is the timed carb diet or timed ketogenic diet (TCD or TKD). In this version, select quantities (and possibly types) of carbohydrates are consumed during regular ketogenic dieting periods to help provide a glucose source during training, as well as enhance recovery and stimulate muscle protein synthesis around workouts. It is well known that the ingestion of liquid carbohydrate around training may serve to promote faster recovery, which may enhance subsequent exercise and training session performance (3). It is also theorized that insulin mediated muscle protein synthesis is enhanced with the inclusion of carbohydrate to a protein/amino acid beverage consumed before, during and after training.

In ketogenic diets, it is common for the dietary carbohydrate amount to not exceed 50g per day (often excluding dietary fiber), or up to 10-percent of total calories. For smaller and/or less active individuals, it would stand to reason that a lower carbohydrate ceiling exists with which they can maintain a ketogenic state. Conversely, for larger and/or more active individuals, it would stand to reason that a slightly higher carbohydrate intake would be permissible. Exact numbers are hard to quantify, and trial and error would be paramount in discovering one’s own tolerance to carbohydrate intake while still reaping the metabolic benefits of a ketogenic diet. A good starting point would be to consume 25g usable carbohydrates along with 25g fiber in the non-workout time period (primarily from vegetables, some nuts and seeds) and include 25g of easily digestible liquid carbohydrate during the training period.

Dietary protein and fat can vary, but may look like this for a 200-pound athlete in a caloric surplus:

Calories: 3,000

Protein: 30%; 900 cals; 225g (providing 1-1.25g/lb BW, spread over 4-6 meals per day)

Fat: 60%; 1800 cals; 200g

Carbs: 10%; 300 cals, 75g (including 25g fiber)

Meal 1: 45g protein, 40g fat, 10g carbohydrate (5g fiber)

Meal 2: 45g protein, 40g fat, 10g carbohydrate (5g fiber)

Meal 3: 45g protein, 40g fat, 10g carbohydrate (5g fiber)

Meal 4: 45g protein, 40g fat, 10g carbohydrate (5g fiber)

Meal 5: 45g protein, 40g fat, 10g carbohydrate (5g fiber)

Workout Drink: 25g liquid carbohydrate (dextrose, high molecular weight carbs, etc.) along with 10-20g BCAA/EAA supplement

Is keto the answer?

In the world of strength and physique sports, there are rarely any black and white, hard and fast answers on most topics. While it certainly isn’t for everyone, ketogenic dieting has many metabolic benefits that traditional higher carbohydrate, lower fat diets don’t necessarily offer. Those who lead a more sedentary lifestyle outside the gym (such as office work) may very well be able to train intensely on a carbohydrate-controlled ketogenic diet. The only way to find out what works best for your situation is to give it a try.

Prepare, Perform, Prevail, Pass the bacon.

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