The quality and type of carbohydrates and fats consumed in the daily diet are associated with the overall risk of diseases and quality of life. But whether the type and quality of carbohydrate and fat intake are correlated with overall mortality is not clear. The objective of this study is to determine the associations of low-carbohydrate and low-fat diets with mortality.

This prospective cohort study included a total of 37,233 adults (mean age 49.7). The overall, unhealthy, and healthy low-carbohydrate-diet and low-fat-diet scores of the participants were calculated. The primary outcome of the study was all-cause mortality from baseline.

Of 37,223 participants and 297,768 person-years of follow-up, a total of 4,866 deaths occurred. The findings suggested that overall low-carbohydrate diet and low-fat diet scores did not show a significant correlation with overall mortality. The multivariable-adjusted hazard ratios (HR) for total mortality were 1.07 for unhealthy low-carbohydrate diet score, 0.91 for healthy low-carbohydrate diet score, 1.06 for unhealthy low-fat diet score, and 0.89 for healthy low-fat diet score.

The research concluded that overall low-carbohydrate and low-fat diet scored did not affect the rate of total mortality. However, unhealthy low-carbohydrate and low-fat intake were associated with higher total mortality.