We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses.
- Authors
Cipryan, Lukas; Plews, Daniel J.; Ferretti, Alessandro; Maffetone, Phil B.; Laursen, Paul B.
- Abstract
The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low- carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT). Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohy- drate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks. Participants performed graded exercise tests (GXT) before and after the ex- periment, and an HIIT session (5x3min, work/rest 2:1, passive re- covery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (... O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal O2 (...O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively. Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in VO2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear. Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory re- sponses to HIIT compared with the HD.
- Subjects
CONFIDENCE intervals; EXERCISE tests; HEART beat; LACTATES; LOW-carbohydrate diet; PHYSICAL fitness; EFFECT sizes (Statistics); OXYGEN consumption; DESCRIPTIVE statistics
- Publication
Journal of Sports Science & Medicine, 2018, Vol 17, Issue 2, p259
- ISSN
1303-2968
- Publication type
Article