Healthy Longevity

What is covered in this review: Ketogenic diets are often promoted to improve body composition but were found to have a negative effect compared to a minimally processed, very-low-fat, plant-based diet in an inpatient feeding study. A meta-analysis of 15 crossover, inpatient feeding studies presented here found that isocaloric substitution of fat with carbohydrate resulted in a 21.6 g/day greater reduction in fat loss (Figure 1). Greater fat loss occurred during the lower fat diets even when there was a rapid and sustained decrease in insulin secretion during carbohydrate restriction. Inpatient feeding studies and a meta-analysis of 21 randomized controlled experiments demonstrate that minimally processed and fiber-rich sources of carbohydrate also lead to lower energy intake, explaining the discrepancies in studies examining ad libitum intake. Large “lifelong” Mendelian randomization studies demonstrate a causal and permanent effect of substituting carbohydrate with dietary fat and gr...