Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial

Abstract

Purpose: This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12 weeks on visceral adipose tissue (VAT) and cardiorespiratory fitness (CRF) level in overfat individuals.Methods: Ninety-one participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Body composition and CRF were analyzed before the experimental period and after 4, 8, and 12 weeks. Dual-energy X-ray absorptiometry (DXA) and graded exercise test (GXT) to volitional exhaustion were used for the body composition and CRF assessments, respectively.Results: There were significant between-group differences in the VAT mass and body composition outcome changes. VAT mass decreased after 12 weeks only in the VLCHF and VLCHF+HIIT groups (p < 0.001, median [95% CI]: VLCHF: −142.0 [−187.0; −109.5] g; VLCHF+HIIT: −104.0 [−135.0; −71.0] g). Similarly, changes in body mass, total body fat, trunk fat mass, waist and hip circumferences were distinctly decreased in the VLCHF and VLCHF+HIIT groups, when compared to HIIT and Control groups. Total lean mass significantly decreased in the VLCHF and VLCHF+HIIT groups (−2.1 [−3.0; −1.6] kg and −2.5 [−3.6; −1.8] kg, respectively) after 12 weeks. While the HIIT program significantly increased total time to exhaustion in the GXT, peak oxygen uptake was unchanged.Conclusions: A VLCHF diet, either in isolation or in combination with HIIT, was shown to induce a significant reduction in VAT mass and body composition variables. HIIT alone did not cause such effects on body composition, but improved exercise capacity. Our findings indicate that the VLCHF diet and exercise training provoked different and isolated effects on body composition and CRF.Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03934476, identifier: NCT03934476.

Very Low-Carbohydrate High-Fat Diet Improves Risk Markers for Cardiometabolic Health More Than Exercise in Men and Women With Overfat Constitution: Secondary Analysis of a Randomized Controlled Clinical Trial

“…The results of the anthropometric analysis have previously been reported ( 6 ). In summary, the total body mass and visceral adipose tissue (VAT) mass significantly decreased in the VLCHF (by median [IQR]: −6.9 ([−8.4; −5.6]) % and −23.2 [−26.5; −14.7] %, respectively) and VLCHF+HIIT (by −9.0 [–10.9; −7.9] % and −17.6 [−23.8; −10.8] %, respectively) groups after 12 weeks despite no significant changes in the HIIT and Control groups.…”

“…It was a randomized, controlled, four-arm, parallel exercise and/or dietary intervention study ( ClinicalTrials.gov : NCT03934476), with the primary aim of examining the VLCHF and HIIT effect on body composition and cardiorespiratory fitness level ( 6 ). The method for random assignment is presented in Supplemental Material .…”

“…Results for the primary outcome were previously reported, that a VLCHF diet, either in isolation or in combination with HIIT, caused a significant reduction in visceral adipose tissue (VAT) mass and body composition variables. HIIT alone did not induce such effects on body composition, but improved exercise capacity ( 6 ). We utilized the infrastructure of this trial to conduct a preplanned ancillary study focused on clinically relevant risk factors of cardiometabolic health.…”

“…While the importance of physical activity for increased fitness is undeniable, exercise alone may not necessarily reduce excess body fat. In a previous randomized controlled clinical trial we showed that a very low-carbohydrate high-fat (VLCHF) diet alone reduced excess body fat in individuals with overfat constitution more than high-intensity interval training (HIIT) alone ( 6 ). Low carbohydrate diets are effective in remission of diabetes ( 7 ) and improve insulin sensitivity as measured by HOMA-IR ( 8 – 10 ).…”

“…A VLCHF diet was previously shown to increase adiponectin/leptin ratio reflecting reduced systemic low-grade inflammation in healthy young individuals ( 16 ). In contrast, the same diet was found to be an effective strategy for reducing excess body fat in men and women with overfat constitution ( 6 ). Systematic reviews and meta-analyses show also beneficial effects of low carbohydrate diets combined with exercise on body composition, triglycerides, and aerobic capacity in adults with obesity ( 17 , 18 ).…”