A prospective US cohort study and meta-analysis suggested that both high and low percentages of carbohydrate diets were associated with increased mortality, with minimal risk observed at 50–55% carbohydrate intake. The association was modified by the source of food, with higher mortality when carbohydrates were exchanged for animal-derived fat or protein and lower mortality when the substitutions were plant-based. The cohort study included 15 428 adults aged 45–64 years (between 1987 and 1989), with a median follow-up of 25 years and 6283 deaths. After multivariable adjustment, there was a U-shaped association between the percentage of energy consumed from carbohydrate (mean 48·9%, SD 9·4) and mortality: a percentage of 50–55% energy from carbohydrate was associated with the lowest risk of mortality. In the meta-analysis of all cohorts (432 179 participants) with 40 181 deaths, both low carbohydrate consumption (<40%) and high carbohydrate consumption (>70%) conferred greater mortality risk than did moderate intake, which was consistent with a U-shaped association (pooled hazard ratio 1·20 for low carbohydrate consumption; 1·23 for high carbohydrate consumption). However, mortality increased when carbohydrates were replaced with animal-derived fat or protein (1·18) and mortality decreased when the substitutions were plant-based (0·82). The findings support benefits of moderate carbohydrate intake and plant-based food, and provide further evidence that animal-based low carbohydrate diets should be discouraged. Source: https://www.thelancet.com/
