A new study has found that consuming carbohydrates in moderation is associated with lower risk of mortality.
 

The study found that diets -- both low (less than 40 per cent energy) and high (more than 70 per cent energy) in carbohydrates -- were linked with an increase in mortality, while moderate consumers of carbohydrates (50-55 per cent of energy) had the lowest risk of mortality.

"These findings bring together several strands that have been controversial. Too much and too little carbohydrate can be harmful but what counts most is the type of fat, protein, and carbohydrate," said co-author Walter Willett, Professor at the Harvard T.H. Chan School of Public Health in Boston.

For the study, published in The Lancet Public Health journal, the team involved 15,428 adults aged between 45 and 64 years. The participants reported consuming 600-4200 kcal per day for men and 500-3600 kcal per day for women. The researchers estimated that from age 50, the average life expectancy was an additional 33 years for those with moderate carbohydrate intake -- four years longer than those with very low carbohydrate consumption (29 years), and one year longer compared to those with high carbohydrate consumption (32 years). 

However, they highlight that since diets were only measured at the start of the trial and six years later, dietary patterns could change over 25 years, which might make the reported effect of carbohydrate consumption on lifespan less certain. The researchers also performed a meta-analysis of data from eight prospective cohorts involving data from 432,179 people in North American, European, and Asian countries. 

This revealed similar trends, with participants whose overall diets were high and low in carbohydrates having a shorter life expectancy than those with moderate consumption. It also showed that low-carb diets that replace carbohydrates with proteins and fats from plant sources associated with lower risk of mortality compared to those that replace carbohydrates with proteins and fat from animal sources.