Journal Article

A Plant-Based High-Carbohydrate, Low-Fat Diet in Overweight Individuals in a 16-Week Randomized Clinical Trial: The Role of Carbohydrates

Dort, Sara, Kahleova, Hana, Holubkov, Richard, Barnard, Neal D.

2018

Overview

The effects of carbohydrates on body weight and insulin sensitivity are controversial. In this 16-week randomized clinical trial, we tested the role of a low-fat, plant-based diet on body weight, body composition and insulin resistance. As a part of this trial, we investigated the role of changes in carbohydrate intake on body composition and insulin resistance. Participants (n = 75) were randomized to follow a plant-based high-carbohydrate, low-fat (vegan) diet (n = 38) or to maintain their current diet (n = 37). Dual-energy X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. A repeated measure ANOVA model was used to test the between-group differences from baseline to 16 weeks. A linear regression model was used to test the relationship between carbohydrate intake, and body composition and insulin resistance. Weight decreased significantly in the vegan group (treatment effect −6.5 [95% CI −8.9 to −4.1] kg; Gxt, p < 0.001). Fat mass was reduced in the vegan group (treatment effect −4.3 [95% CI −5.4 to −3.2] kg; Gxt, p < 0.001). HOMA-IR was reduced significantly in the vegan group (treatment effect −1.0 [95% CI −1.2 to −0.8]; Gxt, p = 0.004). Changes in consumption of carbohydrate, as a percentage of energy, correlated negatively with changes in BMI (r = −0.53, p < 0.001), fat mass (r = −0.55, p < 0.001), volume of visceral fat (r = −0.35, p = 0.006), and HOMA (r = −0.27, p = 0.04). These associations remained significant after adjustment for energy intake. Changes in consumption of total and insoluble fiber correlated negatively with changes in BMI (r = −0.43, p < 0.001; and r = −0.46, p < 0.001, respectively), fat mass (r = −0.42, p < 0.001; and r = −0.46, p < 0.001, respectively), and volume of visceral fat (r = −0.29, p = 0.03; and r = −0.32, p = 0.01, respectively). The associations between total and insoluble fiber and changes in BMI and fat mass remained significant even after adjustment for energy intake. Increased carbohydrate and fiber intake, as part of a plant-based high-carbohydrate, low-fat diet, are associated with beneficial effects on weight, body composition, and insulin resistance.

• Publisher: MDPI AG,MDPI
• Subject: Adiposity / Adult / Aged / Biomarkers - blood / Blood Glucose - metabolism / body mass index / carbohydrate intake / carbohydrates / Clinical trials / Diet, Fat-Restricted / Diet, Vegan / Dietary Carbohydrates - administration & dosage / Dietary Carbohydrates - metabolism / Dietary fiber / Dietary Fiber - administration & dosage / dual-energy X-ray absorptiometry / Energy intake / Female / Grain / homeostasis / Humans / insoluble fiber / Insulin - blood / Insulin Resistance / low fat diet / Male / Middle Aged / Obesity / overweight / Overweight - blood / Overweight - diagnosis / Overweight - diet therapy / Overweight - physiopathology / Plant Proteins, Dietary - administration & dosage / Plant Proteins, Dietary - metabolism / plant-based diet / randomized clinical trials / regression analysis / Time Factors / Treatment Outcome / vegan diet / Veganism / visceral fat / Weight Loss