Fasting diets could increase the risk of diabetes, according to data presented at the European Society of Endocrinology's annual meeting.
Researchers, led by Ana Bonassa and colleagues from the University of Sao Paulo, Brazil, found that fasting every other day in an effort to lose weight actually impairs the action of insulin and, in turn, may increase the risk of developing diabetes.
"This is the first study to show that, despite weight loss, intermittent fasting diets may actually damage the pancreas and affect insulin function in normal healthy individuals, which could lead to diabetes and serious health issues," Bonassa says in a statement from the society.
Intermittent fasting diets have gained popularity as a way to lose weight while still eating regularly onmost days. Several celebrities such as Jimmy Kimmel and Hugh Jackman have reported using a type of fasting diet to shed pounds, but researchers have questioned the safety of these diets.
To learn more, Bonassa and colleagues studied the impact fasting every other day has on body weight, free radical levels, and insulin function in healthy adult rats. The rats were studied over a three-month period.
Researchers found that the amount of fat tissue in the abdomen in the rats increased during the study period and cells of the pancreas that release insulin had been damaged. They also noted markers of insulin resistance were present and the free radical levels had increased in study subjects, according to the release.
This study was conducted on animals; however, researchers believe it could have important implications for humans, particularly those who already have metabolic concerns.
"We should consider that overweight or obese people who opt for intermittent fasting diets may already have insulin resistance, so although this diet may lead to early, rapid weight loss, in the long-term there could be potentially serious damaging effects to their health, such as the development of type-2 diabetes," Bonassa says.
According to the American Diabetes Association, 30.3 million Americans had diabetes in 2015. Diabetes was also the seventh leading cause of death in the United States in 2015 and has been linked to $327 billion in total costs in the United States in 2017.