Ketogenic diets are superior for fat loss short term, but long term there are identical fat losses when calories are matched. Ketogenic diets don’t affect muscle strength but can result in reductions in performance for anaerobic exercise.
GAINING MUSCLE ON KETO SUMMARY
- Building muscle on a keto diet may seem challenging, especially when compared to higher-carb diets. Nevertheless, it is possible to gain muscle on keto, provided the intake of protein and macros aligns with those of high-carbohydrate diets.
- Coffee, coupled with a Keto diet are good combinations to enhance fat mobilization.
- Furthermore, research studies on a keto diet and testosterone levels show that adding more fat above 30% will not increase testosterone levels. However, keto muscle twitching/ muscle cramps on keto is a common result of electrolyte imbalance.
9/28 RESEARCH UPDATE: KETOGENIC DIETS MAY BE BETTER FOR FAT LOSS BUT GAINING MUSCLE ON KETO MAY BE MORE DIFFICULT
If your goal is to lose weight and fat loss, a new review suggests that keto diets are more favorable than low-fat diets. Interestingly, the review also found that gaining muscle on keto was less effective and reduced performance. The literature review examined keto diet studies (i.e., 60-80% of the calories from fat), with less than 10% of calories coming from carbohydrates or <50 grams of carbs per day.
The non-keto diets included any study that used over 40% of their calories from carbohydrates. The researchers found 16 studies that fit their criteria and looked at muscle mass, fat loss, 1-RM strength, and cycling performance. Through their analysis, the researchers found keto diets were highly effective for fat loss but favored higher carbohydrates for increasing muscle mass, increasing 1-RM strength, and performing high-intensity exercise.
Therefore, gaining muscle on ketogenic diets may be less effective than a higher carb diet. Conversely, a ketogenic diet can work well if fat loss is your main goal. (51)
In essence, muscle on keto is possible, but the diet may be less effective than a diet with carbohydrates. Keto may be better for dieting while trying to maintain muscle, whereas in the off-season, adding more carbs can be beneficial.
7/3/2022 NEW META-ANALYSIS ON GAINING MUSCLE ON KETO AND BODY COMPOSITION
The controversy of gaining muscle on keto is nothing new, but the research has been consistently clear that ketogenic diets will result in better short-term fat loss. In contrast, long term, there is no difference in fat loss compared to low-fat diets when protein and calories are similar.
Recently, a 2022 meta-analysis on ketogenic diets and body composition was released in the Journal of Critical Reviews in Food Sciences and Nutrition. The great part about this review is that it only used trained athletes in the analysis, eliminating people just starting to train and making large increases in strength and lean muscle mass.
Surprisingly, ketogenic diets still have a large following, and many people get quite angry if you tell them a ketogenic diet results in lean muscle loss. They will usually give you a testimonial that they are in the best shape of their life and have been on keto for x amount of years. In this context, the review examined 18 studies and examined performance, strength, and body composition outcomes for all the studies.
The study revealed that ketogenic diets resulted in worse outcomes in cycling performance, 1-RM strength tests (i.e., women performed worse on ketogenic diet strength tests than men), and reduced lean muscle mass. However, ketogenic diets were more effective for reducing body weight and fat loss than low-fat/high-carbohydrate diets. (49) Additionally, these findings are similar to another 2021 meta-analysis of 13 studies that found that ketogenic diets resulted in greater fat loss but fewer gains in lean muscle mass. (50)
In sum, the author suggested ketogenic diets may benefit athletes during a non-competitive phase when performance is not a priority and loss of body fat is needed.
Furthermore, the author of the meta-analysis emphasized that the study interventions were only 12 weeks long and that more research is needed for longer-term studies. Nevertheless, from the studies, there does not seem to be an advantage to using ketogenic diets for weight loss, and fat loss is similar when calories and protein are controlled.
KETOSIS AND GAINING MUSCLE ON KETO
There has never been a more controversial subject than gaining muscle on keto diets and muscle loss. Notably, ketogenic diets are characterized by high-fat and moderate to high protein content but an insufficient level of carbohydrates (usually 20 g-50 g per day), thus forcing the body to primarily use fat as a fuel source. In essence, the ketogenic diet mimics metabolic starvation, increasing the body’s use of fat as an energy source.
THE EVOLUTION OF THE KETO DIET: FROM BACON TO KETO BOMBS
The original keto diet was high in saturated fat, low in carbohydrates, and low in protein. In a 4:1 ratio of fat to protein and carbs, 90% of calories come from fat, 6% from protein, and 4% from carbs.
Today, it is known that muscle protein synthesis is extremely important for muscle growth, so the newer versions of the keto diet have all increased the amount of protein to consume daily. There are at least 10 versions of the keto diet, such as the Lean Keto Diet, Keto Carnivore Diet, Keto Green Diet, Keto Liquid Diet, Keto 2.0 Diet, etc.
Famous keto bodybuilders to advocate this lifestyle are Vince Gironda, Clarence Bass, Serge Nubret, Samir Bannout, and Frank Zane. There are thousands of build muscle on keto Reddit threads. Joe Rogan Keto Diet is a long list of celebrities who endorse the low-carb lifestyle.
The reduction of dietary carbohydrates decreases plasma insulin and increases glucagon; this state promotes liver glycogen breakdown and gluconeogenesis (i.e., creation of glucose from non-carbohydrate sources) and lipolysis of adipose tissue through the increase of HSL (hormone-sensitive lipase).(1) Shifting from carbohydrates as a fuel source to fat is known as ketosis.
Based on the evidence, ketogenic diets increase the concentration of ketone bodies in the blood, usually above >0.5 mmol/L, indicating nutritional ketosis.(2) As the brain depends on glucose when following a ketogenic diet, the brain depends on ketone bodies as an energy source.(3) Ketone bodies are present under fed states; however, ketones increase with fasting, prolonged exercise, and reduced carbohydrate availability.
PROTEIN AND FAT
Ketogenic diets are effective for weight loss by increasing satiety and reducing appetite. In a systemic review of the literature, the keto diet resulted in a negative energy balance of -339 kcals per day compared to a control diet.(4)
Many studies in which subjects were not restricted by calories showed ketogenic diets resulted in lower calorie intake.(5, 6) However, when calories are matched (i.e., same calorie deficit), there are no significant differences in losing body weight or fat over a year.(7-9)
Based on the evidence, ketogenic diets result in more weight loss short term; however, there are no differences in fat loss or body weight long term compared to high carbohydrate, low-fat diets.(10) Furthermore, there is no evidence that a ketogenic diet is superior for fat loss to a high-carbohydrate, low-fat diet in the long term when calories are equal.
RULE #1 FOR GAINING MUSCLE ON LETO: EAT ENOUGH PROTEIN ON KETO
The decreases in appetite have been attributed to the high protein consumed on ketogenic diets and increased appetite-suppressing hormones (i.e., decreased leptin, ghrelin, etc.), resulting in a lower caloric intake. Others have suggested the increased fiber from consuming more vegetables also contributes to the reduced caloric intake.
Thus, keto reduces caloric intake compared to control diets. Some have touted that ketogenic diets result in a “metabolic advantage” resulting in increased energy expenditure, but this was disproven by Kevin Hall.
He showed that a ketogenic diet resulted in about a 100 kcal increase in energy expenditure after adjusting for body mass and composition.(11) The data from several studies suggest that the metabolic advantage of a ketogenic diet would be small, certainly not enough to make it superior to that of a carbohydrate-matched diet.
Ketogenic diets also increase circulating ketones. Several supplement companies have also developed products to boost ketone levels, such as KETO BURN DIET PILL and exogenous ketones. A Keto diet fiber supplement is also recommended for those who do not consume vegetables.
KETOSIS AND GAINING MUSCLE ON KETO
Several studies have shown that exogenous administrations of ketone metabolites that increase ketones without carbohydrate restriction demonstrate anti-catabolic and anti-inflammatory properties. (12, 13)
Specifically, in endurance athletes, the administration of ketone esters has increased markers of recovery by preventing overtraining and overreaching.(14) Interestingly, despite symptoms of overreaching, the ketone supplemented group improved their overall work output and endurance performance test by 15% compared to the control group.
In the context of animal models, cancer-induced muscle wasting can be prevented with supplemental ketones.(15) Furthermore, others have found that ketone esters could increase anabolic signaling pathways in muscle (i.e., mTOR). (16)
However, despite these properties of ketones, most of the studies that have compared ketogenic diets to isocaloric diets with resistance exercise have found either decrease (17-20), similar changes(19, 21-26), or increases(25, 27) in lean muscle mass. In addition, the Wilson et al. study, the ketogenic diet was followed with a carbohydrate refeed in the post-evaluation period, likely enhancing glycogen and positively influencing the final lean mass results.(25)
GAINING MUSCLE ON KETOGENIC DIETS
Most of the earlier studies on ketogenic diets used low protein diets; however, the studies in elite athletes found that a high protein (i.e., 30-40% protein) ketogenic diet maintained muscle mass.(28, 29) In sum, ketogenic diets can maintain lean mass but do not seem productive for increasing muscle mass.
Hence, most research suggests that combining a ketogenic diet with resistance training can favor a fat mass reduction in healthy and trained individuals. However, muscle mass may also be compromised.(30) Another consequence of a low-carbohydrate diet are feeling of fatigue or what has been referred to as the “Keto-flu.”(31) Furthermore, several meta-analyses have found that ketogenic diets are beneficial for losing body fat but are not favorable for increasing lean muscle mass.(4, 32, 33)
In sum, a ketogenic diet can maintain lean muscle mass as long as the protein intake is sufficiently high, ~1.7 g/kg/day or .8 grams per pound, but the studies do not show it’s beneficial for increasing lean muscle mass. Conversely, Others have found reductions in anabolic signaling pathways (i.e., mTOR, AMPK) and reduced anabolic hormones (i.e., testosterone and IGF-1), which could contribute to the reduced increases in lean mass.(20, 34-36)
KETOGENIC DIETS AND GLYCOGEN
The large increases in lean mass on a ketogenic diet can be attributed to increased water loss as ketones increase water loss and large reductions in glycogen (i.e., every gram of glycogen holds 3 grams of water).(37-39) Consequently, the larger increases in body weight losses with ketogenic diet over low-fat diets during short-term interventions are attributed to losses in body water.
Well-hydrated muscles account for almost 75% of the water content. For example, a study of bodybuilders who underwent a carbohydrate loading protocol before a show increased the size of their chest, thighs, arms, calves, etc., compared to a group that did not carb load before a competition.(40) Most studies measuring body composition using dual-energy X-ray absorptiometry or DEXA heavily rely on measuring body water content; thus, researchers don’t know whether there are actual losses in lean body mass or just water weight.
True Muscle Loss and Water Loss
Therefore, the losses of lean muscle mass in studies can incorrectly assume its lean mass when it could just be water weight loss. DEXA is widely used for its ease of use, but DEXA has been found to have a 4% error and has been found to poorly accurately detect changes in lean mass in response to resistance exercise. DEXA does not have the accuracy in detecting small to moderate increases in muscle size.(41)
“In a review of the literature on carbohydrate intake and its relationship to increasing muscle mass. Most studies found no significant difference in lean mass or body composition when protein intake and calories were similar.”
“The studies that showed higher carbohydrate diets resulted in greater gains in muscle mass can be confounded by the group consuming high carbohydrates also had a higher total energy intake. It could be the high carbohydrate group gained more muscle because they were eating more calories. Being in a caloric surplus always makes it easier to gain muscle.”
— HENSELMANS (2022)