A ketogenic diet aims to induce physiological ketosis (i.e., an increase in levels of ketone bodies in the blood, typically to levels above 0.5 mmol/L) through severe restriction of carbohydrate intake, typically to less than 50 grams of carbohydrate per day or to less than 10% of total energy intake from carbohydrate. Ketogenic diets are an increasingly popular option among endurance athletes and people interested in fat loss,[1] including bodybuilders and strength athletes.
Longitudinal studies of resistance-trained individuals consistently show that a ketogenic diet is inferior to a higher-carbohydrate diet for muscle gain.[2][3][4][5] However, a limitation of these studies is that the group consuming a ketogenic diet lost a significant amount of body weight. A hypocaloric diet is known to facilitate a catabolic environment, including a breakdown of muscle proteins and an impairment in muscle protein synthesis and anabolic signaling pathways.[6]
One 8-week randomized controlled trial in resistance-trained men that did a better job of equating energy intake between groups reported that a higher-carbohydrate diet increased lean body mass compared to a ketogenic diet.[7]
Collectively, these studies suggest that the primary reason a ketogenic diet is inferior for muscle gain is its appetite-suppressing effect,[8] negating the ability to achieve positive calorie balance. However, there are some other reasons to think that a ketogenic diet may be less anabolic than a higher-carbohydrate diet.
Because hypertrophy-oriented resistance exercise is primarily fueled by carbohydrate,[9][10][11] a ketogenic diet could impair resistance exercise performance — the primary stimulus for muscle gain — by limiting the regeneration of adenosine triphosphate (ATP), expediting the onset of muscle fatigue, and impairing the muscles’ ability to contract with high force.[12][13][14]
Additionally, ketogenic diets may induce a “fasting-like” state, causing a potential shift in the balance of anabolic and catabolic pathways in skeletal muscle;[15] namely, increasing the activation of the AMPK pathway, which signals to activate protein breakdown and suppress mammalian target of rapamycin (mTOR) signaling, a central regulator of protein synthesis and muscle growth.
Although it is possible to gain muscle on a ketogenic diet given adequate energy and protein intake, taken together the evidence suggests that more muscle gain can be achieved on a higher-carbohydrate diet.[16]
References
- ^Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide TVery-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trialsBr J Nutr.(2013 Oct)
- ^Greene DA, Varley BJ, Hartwig TB, Chapman P, Rigney MA Low-Carbohydrate Ketogenic Diet Reduces Body Mass Without Compromising Performance in Powerlifting and Olympic Weightlifting AthletesJ Strength Cond Res.(2018 Dec)
- ^Paoli A, Cenci L, Pompei P, Sahin N, Bianco A, Neri M, Caprio M, Moro TEffects of Two Months of Very Low Carbohydrate Ketogenic Diet on Body Composition, Muscle Strength, Muscle Area, and Blood Parameters in Competitive Natural Body Builders.Nutrients.(2021-Jan-26)
- ^Kephart WC, Pledge CD, Roberson PA, Mumford PW, Romero MA, Mobley CB, Martin JS, Young KC, Lowery RP, Wilson JM, Huggins KW, Roberts MDThe Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot StudySports (Basel).(2018 Jan 9)
- ^Salvador Vargas-Molina, Jorge L Petro, Ramón Romance, Richard B Kreider, Brad J Schoenfeld, Diego A Bonilla, Javier Benítez-PorresEffects of a ketogenic diet on body composition and strength in trained womenJ Int Soc Sports Nutr.(2020 Apr 10)
- ^Carbone JW, McClung JP, Pasiakos SMRecent Advances in the Characterization of Skeletal Muscle and Whole-Body Protein Responses to Dietary Protein and Exercise during Negative Energy Balance.Adv Nutr.(2019-01-01)
- ^Vargas S, Romance R, Petro JL, Bonilla DA, Galancho I, Espinar S, Kreider RB, Benítez-Porres JEfficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trialJ Int Soc Sports Nutr.(2018 Jul 9)
- ^Gibson AA, Seimon RV, Lee CM, Ayre J, Franklin J, Markovic TP, Caterson ID, Sainsbury ADo ketogenic diets really suppress appetite? A systematic review and meta-analysisObes Rev.(2015 Jan)
- ^P A Tesch, E B Colliander, P KaiserMuscle metabolism during intense, heavy-resistance exerciseEur J Appl Physiol Occup Physiol.(1986)
- ^Robergs RA, Pearson DR, Costill DL, Fink WJ, Pascoe DD, Benedict MA, Lambert CP, Zachweija JJMuscle glycogenolysis during differing intensities of weight-resistance exercise.J Appl Physiol (1985).(1991-Apr)
- ^MacDougall JD, Ray S, Sale DG, McCartney N, Lee P, Garner SMuscle substrate utilization and lactate production.Can J Appl Physiol.(1999-Jun)
- ^Jacobs I, Kaiser P, Tesch PMuscle strength and fatigue after selective glycogen depletion in human skeletal muscle fibers.Eur J Appl Physiol Occup Physiol.(1981)
- ^Leveritt and AbernethyEffects of carbohydrate restriction on strength performanceThe Journal of Strength and Conditioning Research.(1999)
- ^Niels Ørtenblad, Håkan Westerblad, Joachim NielsenMuscle glycogen stores and fatigueJ Physiol.(2013 Sep 15)
- ^Paoli A, Bianco A, Grimaldi KAThe Ketogenic Diet and Sport: A Possible Marriage?Exerc Sport Sci Rev.(2015-Jul)
- ^Ashtary-Larky D, Bagheri R, Bavi H, Baker JS, Moro T, Mancin L, Paoli AKetogenic diets, physical activity and body composition: a review.Br J Nutr.(2021-Jul-12)