Metabolic Effects of Weight Loss on a Very-Low-Carbohydrate Diet Compared With an Isocaloric High-Carbohydrate Diet in Abdominally Obese Subjects

Objectives This study was designed to compare the effects of an energy-reduced, isocaloric very-low-carbohydrate, high-fat (VLCHF) diet and a high-carbohydrate, low-fat (HCLF) diet on weight loss and cardiovascular disease (CVD) risk outcomes. Background Despite the popularity of the VLCHF diet, no studies have compared the chronic effects of weight loss and metabolic change to a conventional HCLF diet under isocaloric conditions. Methods A total of 88 abdominally obese adults were randomly assigned to either an energy-restricted (∼6 to 7 MJ, 30% deficit), planned isocaloric VLCHF or HCLF diet for 24 weeks in an outpatient clinical trial. Body weight, blood pressure, fasting glucose, lipids, insulin, apolipoprotein B (apoB), and C-reactive protein (CRP) were measured at weeks 0 and 24. Results Weight loss was similar in both groups (VLCHF −11.9 ± 6.3 kg, HCLF −10.1 ± 5.7 kg; p = 0.17). Blood pressure, CRP, fasting glucose, and insulin reduced similarly with weight loss in both diets. The VLCHF diet produced greater decreases in triacylglycerols (VLCHF −0.64 ± 0.62 mmol/l, HCLF −0.35 ± 0.49 mmol/l; p = 0.01) and increases in high-density lipoprotein cholesterol (HDL-C) (VLCHF 0.25 ± 0.28 mmol/l, HCLF 0.08 ± 0.17 mmol/l; p = 0.002). Low-density lipoprotein cholesterol (LDL-C) decreased in the HCLF diet but remained unchanged in the VLCHF diet (VLCHF 0.06 ± 0.58 mmol/l, HCLF −0.46 ± 0.71 mmol/l; p