Meaty Low Carbohydrate Diets Like Keto and Paleo Could Reduce Life Expectancy, Says New Study

New research suggests that low carbohydrate diets, especially those with a focus on meat and dairy such as the Keto diet, may shorten your life.

The study, which was published in The Lancet Public Health, analyzed data from 16,428 adults in the U.S. over a span of 25 years. The researchers investigated the link between the percentage of energy made up of carbohydrates and all-cause morality, taking into consideration potential non-linear relationships.

Researchers also completed a review of multiple international dietary studies, which featured 432,000 participants in total.

Those who consumed a moderate amount of carbohydrates (50-55 percent of their daily calorie intake) showed lower mortality rates when compared to individuals who followed low carbohydrate diets (below 40 percent of calories). High carbohydrate diets (more than 70 percent) also posed health risks.

Mortality rate was also influenced by the type of fat or protein used to substitute carbohydrates. “These findings bring together several strands that have been controversial,” said Professor Walter Willett, an epidemiologist at the Harvard TH Chan School of Public Health and one of the study’s authors. “Too much and too little carbohydrate can be harmful but what counts most is the type of fat, protein, and carbohydrate.”

Those adhering to low carbohydrate diets typically replace pasta, bread, and other items with extra protein and fats. The Keto diet and the Paleo diet are popular renditions that typically hold a large focus on animal-based foods. However, according to the experts, the healthiest low carbohydrate diets feature plant-based food, such as vegetables, plant oils, and pulses. In the study, those who opted for plant-based fats and proteins had a longer life expectancy than those who chose animal-derived foods.

Low-carbohydrate, high-animal product diets are likely to cause inflammation, biological ageing, and oxidative stress, the researchers said, adding that such diets are linked to a shorter lifespan and “should be discouraged.” In contrast, they noted that when reducing carbohydrate intake, using plant-based fats and proteins as substitutes could “promote healthy ageing.”

Professor Nita Forouhi, an epidemiologist from the University of Cambridge, noted that, “Current guidelines have been criticised by those who favour low carb diets, largely based on short-term studies for weight loss or metabolic control in diabetes, but it is vital to consider long-term effects and to examine mortality, as this study did.” She also noted that followers of the “cult of low carb” would likely disregard the growing body of evidence linking the diet to health implications.