Is intermittent dietary carbohydrate restriction more effective than calorie restriction?

Individuals who adhere to intermittent low-carbohydrate diet (ILCD) show no difference in changes from baseline in obesity measures, glucose regulation, and inflammation compared with those on intermittent calorie restriction diet (ICR) despite trends in reduction in these parameters, a study has shown. However, some differences in responses in lipids and gut microbiota have been observed.

Both ILCD and ICR resulted in decreases in body weight, waist circumference, fasting glucose, insulin, postprandial glucose variation, monocyte chemoattractant protein-1, free fatty acid, and fibroblast growth factor 21.

On the other hand, ILCD compared with ICR yielded significantly different changes in the following outcomes: greater increases in low-density lipoprotein cholesterol (LDL-C) and total cholesterol (‒0.36 mmol/L, 95 percent confidence interval [CI], ‒0.68 to ‒0.04; ‒0.40 mmol/L, 95 percent CI, ‒0.73 to ‒0.06) and a greater reduction in triglyceride (0.20 mmol/L, 95 percent CI, 0.04‒0.37).

In addition, ILCD, but not ICR, led to decreases in Actinobacteria and Bifidobacterium. Such reductions were robustly associated with changes in fasting glucose (r, 0.84 for both) and LDL-C (r, ‒0.81 and ‒0.72, respectively).

This study included 34 participants aged 9 to 30 years with cardiometabolic risk. They were randomly assigned to receive either a self-administered 2-week ILCD (carbohydrate intake ≤50 g/d on 7 nonconsecutive days) or ICR (500‒600 kcal/d for 2 consecutive days per week). The researchers then compared the differences in changes in obesity measures, glycaemic and lipid profiles, gut microbiota composition, and three serum biomarkers.