Scientists fed fruit flies a diet to make them extra plump. In their old age, the researchers put them on a diet and found remarkable results. If the findings transfer to humans, it might mean we can improve our health at any age by cutting calories.
While fruit flies might not seem like the closest human relatives, the diminutive insects actually share about 75% of our DNA, so they are frequently used in scientific studies. They also share a fair amount of the same metabolic pathways as humans, so studies relating to diet can be particularly useful for findings that might apply to human health.
For this go around, researchers at the University of Connecticut School of Medicine put a batch of male fruit flies on a high calorie diet to cause them to become obese. They also restricted the calorie intake of a different group of flies. The calorie-restricted flies were able to live to a maximum of 120 days, which is relatively old for the flies. The fat flies on the high-calorie diet only lived, on average, less than 80 days.
But what really surprised the researchers is that switching diets, even later in life, was able to extend the flies' lifespans. When young flies were switched from a high-calorie to a low-calorie diet at 20 days, they lived almost as long as the flies that had spent their whole lives eating less. Even more notably, when the fat flies were switched to a low-calorie diet at 50 or 60 days – a point at which most of their plump cohorts had already died – the researchers saw extended lifespans and improved metabolisms.
“The remarkable finding of this study is that even after living a significant portion of their lives on a high calorie diet, flies can gain the benefits of life span extension by simply switching to a low calorie diet,” said UConn School of Medicine Genetics and Genome Sciences Chair Brent Graveley.
The findings correspond to work that was done earlier this year in which fruit flies were fed high-fat diets for different daily cycles. One group was allowed to eat for 24 hours, while the other could only feast for 12 hours a day. That study showed that the time-restricted feeding (TRF) flies had better muscle performance, reduced intramuscular fat, and better insulin resistance.
Calorie-restriction has not only proven effective in animal models. In October, a study from the National Institutes of Health showed that humans who were able to reduce their calorie intake even by a modest 12% saw several health and aging markers improve including those related to inflammation, skeletal muscle formation, and overall muscle repair.
The current research has been published in the journal PNAS.
Source: University of Connecticut via EurekAlert