Moderate carbohydrate intake may be best for health, study suggests. A new study has found that diets both low and high in carbohydrates were linked with an increase in mortality, while moderate consumers of carbohydrates had the lowest risk of mortality. The study also found that low-carb diets that replace carbohydrates with proteins and fats from plant sources were associated with lower risk of mortality compared to those that replace carbohydrates with proteins and fat from animal sources. Source 4d.