Researchers from Brigham and Women's Hospital in Boston recently conducted a study, published in the Lancet, to determine the long-term effects of restricting carbohydrates.
To do so, they examined more than 15,000 people ages 45 to 64. The participants completed surveys about the types of food and drink they consumed and their portion sizes. The analysts then calculated their average caloric intake from carbohydrates, proteins and fats and followed up after about 25 years.
After analyzing the information, they found that those who got 50 to 55 percent of their energy from carbohydrates, which they considered moderate, had a lower risk of death, compared to the low- and high-carb groups.
"Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight loss strategy," Sara Seidelmann said in a statement. "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."
Upon further investigation, they discovered low-carb diets full of plant-based proteins and fats, such as nuts and legumes, were particularly linked to a lower risk of death, compared to those rich in animal proteins and fats, such as beef, lamb, pork, chicken and cheese.
The authors believe Western diets with few carbs result in people eating eat less fruits, vegetables and grains and more animal fats and proteins.
“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,” Seidelmann explained.
Their findings also revealed the average life expectancy after age 50 was an additional 33 years for those who ate carbs moderately. That’s four years longer than those with very low carb consumption and one year longer than those with high carb consumption.
The scientists did note their study was observational and does not prove cause and effect. They also acknowledged limitations. The data they reviewed was self-reported, and they said dietary patterns could have changed over time.
Nevertheless, coauthor Scott Solomon said, “This work provides the most comprehensive study of carbohydrate intake that has been done to date, and helps us better understand the relationship between the specific components of diet and long term health.”