17 Aug 2018 --- Following a low-carb diet could shorten life expectancy by four years, suggests new research published in The Lancet Public Health. The high levels of animal fats and proteins that often replace carbohydrates in typical low-carb diets appear to be associated with the higher risk of mortality. Eating more plant-based proteins and fats in place of carbohydrates was linked to lower mortality and even reversed the greater mortality risk.