The mice switching from high-fat to low-fat diet every four weeks prolonged their life span with 25% and reproduced improved blood glucose levels compared to obese mice; similar results were recorded by the mice in the low-fat diet control group.
Although experts invoke the negative effects of Yo-Yo dieting, the new study introduced at the yearly meeting of the Endocrine Society in Boston, supports yo-yo dieting to obesity or lack of any diet program.
“If the conventional wisdom is true, it would discourage a lot of overweight people from losing weight,” said study lead author Edward List, a scientist at Ohio University’s Edison Biotechnology Institute. “The new research shows that the simple act of gaining and losing weight does not seem detrimental to lifespan.”
Statistically, 34% of the American adult population is overweight and 34% is obese (The Centers for Disease Control and Prevention). Weight-loss is maintained by a reduced number of people out of the millions dieting every year.
List et al. performed the first yo-yo dieting study on mice undergoing three diet programs over two years time. Mice undergoing high-fat diet would eat and weigh more and record increased body fat and fasting blood glucose. Eventually mice developed intolerance to glucose or pre-diabetes. The National Institutes of Health, AMVETS and Ohio University supported List’s study.
Although the levels of blood glucose and weight deteriorated during the high-fat diet period, the mice in the yo-yo program registered normal results within the low-fat periods. Their lifespan recorded 2.04 years in comparison with the 1.5 years of the high-fat diet group and 2.09 years of the low-fat diet group.
As ideal as a study on humans would seem, List suggested that a long-term controlled diet program on mice would prove more helpful in observing other influencing factors on weight changes such as illness.
“The study adds to our understanding of the benefit of losing weight,” he said. “I would hope that this encourages people to not give up.”
List intends to conduct the study on an extended group of mice further exploring the possible reduction of cytokaine levels. A high level of cytokaine is currently connected to inflammatory symptoms recorded in certain conditions like diabetes, heart disease and cancer.
Jacob Wright-Piekarski, medical student with St. Louis University, Darlene Berryman, an associate professor in the College of Health Sciences and Professions and John Kopchick, Goll-Ohio Eminent Scholar of molecular biology in the College of Osteopathic Medicine were co-authors of the List research.