A recent study published in The Lancet on the long-term effects of low- and high-carbohydrate diets has highlighted some findings that are not necessarily in line with short-term weight-loss programs. Researchers found that people whose carb intake made up less than 40 percent or more than 70 percent of their daily calories had a higher risk of mortality than people who consumed a moderate amount of carbohydrates. Those who got approximately 50-55 percent of their energy (from calories) in carbohydrates had the lowest risk of an early death.
Perhaps more important than the focus on carbs was what the researchers found about the other food consumed. In popular diets, such as Atkins, many people replace carbohydrates with protein from animals. Increasing the amount of animal fat consumed was associated with earlier death than replacing carbs with plant-based nutrition. Researchers concluded:
Our findings suggest a U-shaped relationship between life expectancy and overall carbohydrate intake, in which lifespan is greatest among people with 50–55% carbohydrate intake, a level that might be considered moderate in North America and Europe but low in other regions, such as Asia. These data provide further evidence that animal-based low carbohydrate diets, which are more prevalent in North American and European populations, should be discouraged. Alternatively, if restricting carbohydrate intake is a chosen approach for weight loss or cardiometabolic risk reduction, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to promote healthy ageing.