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

Abstract

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.

• Authors: Hana Kahleova, Sara Dort, Richard Holubkov, Neal D Barnard
• Journal: Nutrients (Nutrients) Vol. 10 Issue 9 (Sep 14 2018) ISSN: 2072-6643 [Electronic] Switzerland
• PMID: 30223451 (Publication Type: Journal Article, Randomized Controlled Trial)

Chemical References

• Biomarkers
• Blood Glucose
• Dietary Carbohydrates
• Dietary Fiber
• Insulin
• Plant Proteins, Dietary

Topics

• Adiposity
• Adult
• Aged
• Biomarkers (blood)
• Blood Glucose (metabolism)
• Diet, Fat-Restricted
• Diet, Vegan
• Dietary Carbohydrates (administration & dosage, metabolism)
• Dietary Fiber (administration & dosage)
• Female
• Humans
• Insulin (blood)
• Insulin Resistance
• Male
• Middle Aged
• Overweight (blood, diagnosis, diet therapy, physiopathology)
• Plant Proteins, Dietary (administration & dosage, metabolism)
• Time Factors
• Treatment Outcome
• Weight Loss