In the past, it was suggested that you couldn’t build muscle on a low-carb/keto diet, but we now know this is not true. For those who like following low-carb and keto diets, the current research suggests that you can have equal increases in muscle mass and reductions in body fat if your keto diet is well structured.
WILL CARB CYCLING INCREASE MUSCLE GAINS SUMMARY
- Many bodybuilders question whether carb cycling increase muscle gains
- Both the cyclical ketogenic and high carbohydrate diets lost identical fat and body weight.
- The high carbohydrate group had greater muscle strength and endurance gains.
- The cyclical ketogenic diet lost more muscle but also more water weight, which could have affected the lean muscle mass measurements.
- A cyclical ketogenic diet is a good idea because it increases food variability and increases key micronutrients and can result in greater diet motivation.
In the past, it was suggested that you couldn’t build muscle on a low-carb/keto diet, but we now know this is not true. For those who like following low-carb and keto diets, the current research suggests that you can have equal increases in muscle mass and reductions in body fat if your keto diet is well structured.
WILL YOU LOSE ALL YOUR GAINS ON KETO?
Over the years, a big flaw in research studies when comparing a keto diet to the standard western diet is that the diets were not matched for calories. Keto and low-carb diets have an appetite-suppressing effect, so many subjects tend to eat less, resulting in lower calories consumed.
To quote Henselmans et al. in their review of carbohydrates and athletic performance, “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 that the high carbohydrate group gained more muscle because they ate more calories. Being in a caloric surplus always makes it easier to gain muscle.”(Henselmans et al., 2022)
Another flaw in older research studies was the low amount of protein consumed on a low-carb diet. Studies in elite athletes consuming a calorie-restricted, high protein (i.e., 30-40% protein) ketogenic diet can maintain muscle mass. (Paoli et al., 2012; Volek et al., 2004)
Most lifters and bodybuilders don’t want to maintain muscle; they want to gain muscle. Several large-scale studies have found that ketogenic diets are beneficial for losing body fat but not for increasing muscle mass. (Amini et al., 2021; Ashtary-Larky et al., 2021)
IS A CYCLICAL KETOGENIC DIET THE KEY TO GAINING MUSCLE?
There are many forms of the keto diet; there is a standard keto or carnivore diet in which a person eats low carbs continuously. There are alternative forms of the keto diet, such as the cyclical keto diet/keto cycle diet, in which there are specific days on which you eat more carbs.
WILL CARB CYCLING INCREASE MUSCLE GAINS?
On your carb days, you can eat rice, sweet potatoes, bread, etc. On your high-carb days, your carb intake increases, but you still stay at calorie maintenance levels and don’t overconsume calories.
A common concern is that the modified keto diet with carbs will kick you out of a state of ketosis. Don’t worry; if you are in a calorie deficit, you can still burn fat while not being in ketosis.
WILL CARB CYCLING INCREASE MUSCLE GAINS? CARB CYCLING VS KETO DIET
A study by Wilson et al. reported a greater gain in muscle when subjects were switched to higher carbohydrates at the end of the diet. The cyclic keto diet group who consumed carbs at the end of the diet gained more muscle mass than the high-carb diet group. (Wilson et al., 2020)
This raises the question of whether consuming a keto diet which periodic increases in carbs (i.e., keto carb cycling), are better than a long-term low-carb diet. Many lifters question how often they should take a break from keto diets to gain muscle.
WILL CARB CYCLING INCREASE MUSCLE GAINS STUDY?
The cyclical ketogenic diet includes weekly periods of ketosis in which you increase healthy fat intake/reduce carbs, followed by high-carb days/low-fat days designed to kick you out of ketosis. For example, Monday thru Friday would be low carbohydrate days, and Saturday and Sunday would be carbohydrate refeed days.
The theory behind this is the concept of fuel shifting. There are periods of high-fat utilization on low-carb days, and high carbohydrates replenish glycogen stores for enhanced anabolism and restoration of high-intensity exercise with carbohydrates.
The Study
For eight weeks, researchers assigned subjects to a cyclical ketogenic diet or a control diet with resistance exercise and cardio. The cyclical ketogenic diet consumed less than 30 grams of carbohydrates. The weekend meal plan consisted of carbohydrates super-compensation days in which 8-10 g/kg/bw or 3.6 to 4.5 grams per pound of body weight were consumed (70% carbohydrate intake, 15% protein, and 15% fat). The control diet comprised 55% of carbohydrates, 30% of fat, and 15% protein.
Results
The groups performed aerobic exercise 3 days a week and resistance exercise 3 days a week for eight weeks. At the end of the study, both groups lost body weight and body fat at the end of eight weeks, but the cyclical ketogenic diet group lost more lean muscle mass. The cyclical ketogenic diet had neutral effects on strength gains, whereas the regular diet had greater strength improvements than the cyclical ketogenic diet group. (Kysel et al., 2020)
Loss of Lean Muscle
Before you dismiss keto carb cycling as ineffective, there are a few major considerations. Body composition was measured for bioelectrical impedance, which is highly inaccurate, so whether the actual losses in muscle were because of actual muscle loss or just fluid loss was not determined. Also, the protein was on the low side (i.e., 15%); most of the high protein keto diet (i.e., 30%) studies showed high protein could maintain muscle mass.
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.(Tavoian et al., 2019)
I think carb refeeds are a good idea for gaining muscle. If you look at the diet refeeds studies, period refeeds don’t influence changes in body composition, but they result in better performance and motivation than continuous dieting. (Peos et al., 2021)
The other benefit of a cyclical ketogenic diet is that greater consumption of foods can be consumed, leading to a greater array of vitamins, minerals, and nutrients. Ketogenic diets can be insufficient in essential micronutrients. (Calton, 2010)
REFERENCES
Amini, M. R., Aminianfar, A., Naghshi, S., Larijani, B., & Esmaillzadeh, A. (2021). The effect of ketogenic diet on body composition and anthropometric measures: A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr, 1-14. https://doi.org/10.1080/10408398.2020.1867957
Ashtary-Larky, D., Bagheri, R., Asbaghi, O., Tinsley, G. M., Kooti, W., Abbasnezhad, A., Afrisham, R., & Wong, A. (2021). Effects of resistance training combined with a ketogenic diet on body composition: a systematic review and meta-analysis. Crit Rev Food Sci Nutr, 1-16. https://doi.org/10.1080/10408398.2021.1890689
Calton, J. B. (2010). Prevalence of micronutrient deficiency in popular diet plans. Journal of the International Society of Sports Nutrition, 7, 24-24. https://doi.org/10.1186/1550-2783-7-24
Henselmans, M., Bjørnsen, T., Hedderman, R., & Vårvik, F. T. (2022). The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review. Nutrients, 14(4). https://doi.org/10.3390/nu14040856
REFERENCES
Kysel, P., Haluzíková, D., Doležalová, R. P., Laňková, I., Lacinová, Z., Kasperová, B. J., Trnovská, J., Hrádková, V., Mráz, M., Vilikus, Z., & Haluzík, M. (2020). The Influence of Cyclical Ketogenic Reduction Diet vs. Nutritionally Balanced Reduction Diet on Body Composition, Strength, and Endurance Performance in Healthy Young Males: A Randomized Controlled Trial. Nutrients, 12(9), 2832. https://doi.org/10.3390/nu12092832
Paoli, A., Grimaldi, K., D’Agostino, D., Cenci, L., Moro, T., Bianco, A., & Palma, A. (2012). Ketogenic diet does not affect strength performance in elite artistic gymnasts. Journal of the International Society of Sports Nutrition, 9(1), 34. https://doi.org/10.1186/1550-2783-9-34
Peos, J. J., Helms, E. R., Fournier, P. A., Krieger, J., & Sainsbury, A. (2021). A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes: A pre-specified secondary analysis of the ICECAP trial. PLoS One, 16(2), e0247292. https://doi.org/10.1371/journal.pone.0247292
Tavoian, D., Ampomah, K., Amano, S., Law, T. D., & Clark, B. C. (2019). Changes in DXA-derived lean mass and MRI-derived cross-sectional area of the thigh are modestly associated. Scientific Reports, 9(1), 10028-10028. https://doi.org/10.1038/s41598-019-46428-w
REFERENCES
Volek, J., Sharman, M., Gómez, A., Judelson, D. A., Rubin, M., Watson, G., Sokmen, B., Silvestre, R., French, D., & Kraemer, W. (2004). Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism, 1(1), 13-13. https://doi.org/10.1186/1743-7075-1-13
Wilson, J. M., Lowery, R. P., Roberts, M. D., Sharp, M. H., Joy, J. M., Shields, K. A., Partl, J. M., Volek, J. S., & D’Agostino, D. P. (2020). Effects of Ketogenic Dieting on Body Composition, Strength, Power, and Hormonal Profiles in Resistance Training Men. The Journal of Strength & Conditioning Research, 34(12), 3463-3474. https://doi.org/10.1519/jsc.0000000000001935
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