Study: Low-carb diets linked to shorter life span

When it comes to managing carbohydrate intake, a recent study warns you shouldn't have too much, but you certainly shouldn't have too little.

What? Explain

In an article published in The Lancet medical journal on Monday, researchers suggested that consuming a diet consisting of more than 70 percent carbohydrates could shave off one year of a person's life. But it also says that consuming a diet consisting of less than 40 percent carbohydrates might send someone to the grave four years early.

The study used self-reported data from more than 15,400 Americans, ages 45-64, and compared the patterns to seven other studies that involved a total of 432,179 participants in over 20 countries.

Subjects were followed for a median of 25 years. From age 50, those who followed a low-carb diet had a life expectancy of another 29 years; those who had a high-carb diet lived another 32 years, and those who consumed a moderate level of carbohydrates lived another 33 years, according to the study.

The researchers concluded those with the lowest risk of an early death followed a diet made up of 50-55 percent carbohydrates.

So, what does this mean?

Experts acknowledge the results of this research will call into question a number of Western diet trends.

Lead author of the study, Sara Seidelmann of Brigham and Women's Hospital in Boston, issued a statement on the findings.

"Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight-loss strategy," Seidelmann said. "However, our data suggests that animal-based low carbohydrate diets, which are prevalent in North America and Europe, might be associated with shorter overall life span and should be discouraged.

"Instead, if one chooses to follow a low carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy aging in the long term," she suggested.

Catherine Collins, a dietitian with the United Kingdom's National Health Service, which was not involved in the study, weighed in on the results.

The findings "will disappoint those who, from professional experience, will continue to defend their low carb cult," she said, "but contributed to the overwhelming body of evidence that supports a balanced approach to caloric intake recommended globally by public health bodies."