Novel Combination of Exercise and Carbohydrate Restriction for Metabolic Health

Date
2020
Authors
Gil-Sotomayor, Abelardo
Supervisor
Harris, Nigel
Williden, Micalla
Kilding, Andrew
Dulson, Deborah
Item type
Thesis
Degree name
Doctor of Philosophy
Journal Title
Journal ISSN
Volume Title
Publisher
Auckland University of Technology
Abstract

Purpose: To compare the effects of iso-time and quasi iso-effort high-intensity interval training (HIIT), resistance training (RT) or both HIIT and RT (COMBO), all with a low carbohydrate high fat diet (LCHF) in sedentary and overweight individuals. Methods: 54 adults (18-60 y, M=24, F=30) were randomised to one of three experimental groups: LCHF+HIIT, LCHF+RT or LCHF+COMBO. For 12 weeks the participants performed their 20 min exercise protocol thrice weekly, while following the LCHF diet (≤100 g CHO, ⁓1.5g PRO/kg and unrestricted fat intake). Sessions involved 10x1 min of high-intensity effort (⁓17 RPE on a 6-20 scale) interspersed with 1 min recovery periods. Target heart rate for HIIT was ≥95% HRR whereas for RT, resistance was set @ ⁓70-80% of maximum, or approximately 2 repetitions short of failure. Outcomes assessed were body composition, blood biomarkers, and performance measures. Results: Adjusted between group differences were analysed with general or generalised linear models. Improvements in HbA1c were significantly greater for LCHF+HIIT than both LCHF+RT (β= 2.41, p=0.014) and LCHF+COMBO (β= 2.58; p=0.005). Body mass reduction was significantly greater for LCHF+HIIT relative to LCHF+COMBO (β= 1.88, p=0.049). Upper body strength was superior for LCHF+RT relative to LCHF+HIIT (β= 4.18; p=0.024). Resting metabolic rate (RMR) was greater for LCHF+COMBO (β= 896.02; p=0.004) and LCHF+RT (β= 690; p=0.024) both relative to LCHF+HIIT. Otherwise, there were no significant differences between groups observed. Conclusion: These combinations of LCHF and exercise were similarly effective for improving cardiometabolic risk factors, potentially due to the high-intensity effort elicited in all three conditions, and the LCHF

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Keywords
Metabolic syndrome , V̇O2peak , Visceral adipose tissue , Resting metabolic rate , Weight loss
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