Effects 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;13(2):374. doi: 10.3390/nu13020374.

Abstract

Background: Ketogenic diet (KD) is a nutritional approach that restricts daily carbohydrates, replacing most of the reduced energy with fat, while maintaining an adequate quantity of protein. Despite the widespread use of KD in weight loss in athletes, there are still many concerns about its use in sports requiring muscle mass accrual. Thus, the present study sought to investigate the influence of a KD in competitive natural body builders. Methods: Nineteen volunteers (27.4 ± 10.5 years) were randomly assigned to ketogenic diet (KD) or to a western diet (WD). Body composition, muscle strength and basal metabolic rate were measured before and after two months of intervention. Standard blood biochemistry, testosterone, IGF-1, brain-derived neurotrophic factor (BDNF) and inflammatory cytokines (IL6, IL1β, TNFα) were also measured. Results: Body fat significantly decreased in KD (p = 0.030); whilst lean mass increased significantly only in WD (p < 0.001). Maximal strength increased similarly in both groups. KD showed a significant decrease of blood triglycerides (p < 0.001), glucose (p = 0.001), insulin (p < 0.001) and inflammatory cytokines compared to WD whilst BDNF increased in both groups with significant greater changes in KD (p < 0.001). Conclusions: KD may be used during body building preparation for health and leaning purposes but with the caution that hypertrophic muscle response could be blunted.

Keywords: health; ketogenic diet; resistance training; strength.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adipose Tissue
  • Adolescent
  • Adult
  • Athletes
  • Basal Metabolism
  • Blood Glucose
  • Body Composition*
  • Brain-Derived Neurotrophic Factor / blood
  • Carbohydrates
  • Cytokines / blood
  • Diet, Carbohydrate-Restricted*
  • Diet, Ketogenic*
  • Diet, Western
  • Glucose
  • Humans
  • Insulin
  • Insulin-Like Growth Factor I
  • Male
  • Muscle Strength / physiology*
  • Muscles
  • Resistance Training
  • Testosterone / blood
  • Triglycerides / blood
  • Weight Loss
  • Young Adult

Substances

  • Blood Glucose
  • Brain-Derived Neurotrophic Factor
  • Carbohydrates
  • Cytokines
  • Insulin
  • Triglycerides
  • Testosterone
  • Insulin-Like Growth Factor I
  • Glucose