Healthy Longevity

What is covered in this review: Dairy foods are widely recommended to promote health but have been associated with an increased risk of premature death when substituted for healthful plant-based alternatives. Meta-analyses of prospective cohort studies found that substituting whole grains, legumes, and nuts with a 200-245 g/day serving of dairy foods, including yogurt, was associated with between a 12% and 28% increased risk of all-cause mortality. A meta-analysis of Mendelian randomization studies involving 119,787 participants presented here found that a genetically predicted 1% increment in energy from total dairy was causally associated with an 8% increased risk of all-cause mortality compared to other typically consumed foods (Figure 1). Genetically predicted dairy intake was causally associated with a 44% increased risk of all-cause mortality in a subgroup analysis in which dairy foods likely predominantly displaced healthful plant foods. A meta-analysis of prospective cohort stu...

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...