The effect of a short-term ketogenic diet on exercise efficiency during graded exercise in healthy adults

Wonhee Cho; Hwaebong Jung; Sunghyun Hong; Hyuk In Yang; Dong-Hyuk Park; Sang-Hoon Suh; Dong Hoon Lee; Yong-Sahm Choe; Joon Young Kim; Wooyoung Lee; Justin Y Jeon

doi:10.1080/15502783.2023.2264278

The effect of a short-term ketogenic diet on exercise efficiency during graded exercise in healthy adults

J Int Soc Sports Nutr. 2023 Dec;20(1):2264278. doi: 10.1080/15502783.2023.2264278. Epub 2023 Oct 4.

Authors

Wonhee Cho^{1

2}, Hwaebong Jung³, Sunghyun Hong², Hyuk In Yang², Dong-Hyuk Park², Sang-Hoon Suh⁴, Dong Hoon Lee^{2

5

6}, Yong-Sahm Choe⁷, Joon Young Kim¹, Wooyoung Lee³, Justin Y Jeon^{2

8

9}

Affiliations

¹ Syracuse University, Department of Exercise Science, David B. Falk College of Sport and Human Dynamics, Syracuse, NY, USA.
² Yonsei University, Department of Sport Industries, Seoul, South Korea.
³ Yonsei University, Department of Materials Science and Engineering, Seoul, South Korea.
⁴ Yonsei University, Department of Physical Education, Seoul, South Korea.
⁵ Harvard T.H. Chan School of Public Health, Department of Nutrition, Boston, MA, USA.
⁶ Nanyang Technological University, Lee Kong Chian School of Medicine, Nanyang, Singapore.
⁷ gIsenlab Inc, iSenLab R&D center, Seongnam, South Korea.
⁸ Yonsei University College of Medicine, Cancer Prevention Center, Yonsei Cancer Center, Seoul, South Korea.
⁹ Yonsei University, Exercise Medicine Center for Diabetes and Cancer Patients, ICONS, Seoul, South Korea.

Abstract

Objective: We examined the effects of short-term KD on exercise efficiency and hormonal response during and after the graded exercise testing.

Methods: Fourteen untrained healthy adults (8 males, 6 females, age 26.4 ± 3.1 [SD] years; BMI 24.8 ± 4.6 kg/m²; peak VO₂max 54.0 ± 5.8 ml/kg FFM/min) completed 3-days of a mixed diet (MD) followed by another 3-days of KD after 3-days of washout period. Upon completion of each diet arm, participants underwent graded exercise testing with low- (LIE; 40% of VO₂max), moderate- (MIE; 55%), and high-intensity exercise (HIE; 70%). Exercise efficiency was calculated as work done (kcal/min)/energy expenditure (kcal/min).

Results: Fat oxidation during the recovery period was higher in KD vs. MD. Despite identical workload during HIE, participants after having KD vs. MD showed higher energy expenditure and lower exercise efficiency (10.1 ± 0.7 vs. 12.5 ± 0.3%, p < .01). After KD, free fatty acid (FFA) concentrations were higher during MIE and recovery vs. resting, and beta-hydroxybutylate (BOHB) was lower at HIE vs. resting. Cortisol concentrations after KD was higher during recovery vs. resting, with no significant changes during graded exercise testing after MD.

Conclusions: Our data suggest that short-term KD is favorable to fat metabolism leading increased circulating FFA and BOHB during LIE to MIE. However, it is notable that KD may cause 1) exercise inefficiency manifested by increased energy expenditure and 2) elevated exercise stress during HIE and recovery. Trial registration: KCT0005172, International Clinical Trials Registry Platform.

Keywords: Ketogenic diet; exercise efficiency; exercise stress.

Publication types

Clinical Trial

MeSH terms

Adult
Diet, Ketogenic*
Energy Metabolism
Exercise / physiology
Exercise Test
Female
Humans
Male
Oxidation-Reduction
Young Adult

Grants and funding

This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF), the Yonsei Signature Research Cluster Project (2021-22-0009). and the Ministry of Science, ICT & Future Planning [2017M3A9F1052297].