Study after study has consistently proven that all creatures, from monkeys to fruit flies to mice to nematodes, survive longer when their fuel source is restricted. AP photo
Cutting calories and habitually holding off on meals just might be a winning strategy for stretching out your years, though terms and conditions may apply.
A large new animal study conducted in the United States on over 1,000 mice reveals that metabolic alterations and a reduction in body mass are side effects of dietary restriction that may come at a health cost for some persons.
Study after study has consistently proven that all creatures, from monkeys to fruit flies to mice to nematodes, survive longer when their fuel source is restricted.
However, given the ethical and logistical limitations of clinical research, it's difficult to predict whether eating less will similarly push the limits of human lifespans.
Observational studies involving less extreme calorie restrictions, such as intermittent fasting, reveal that dietary restriction has benefits that may lessen our own odds of dying prematurely.
Health studies also suggest weight and body fat reductions, as well as reduced cardiometabolic risks, which could play a significant role in life extension. However, small sample sizes and short study periods make it difficult to determine if these changes are directly responsible for the increased lifespan.
Researchers studied the effects of graded calorie restriction and intermittent fasting on 960 genetically varied female mice, confirming prior research that suggests that keeping the body a bit hungry from time to time leads to somewhat longer lives.
Those with the biggest calorie reduction lost, on average, over a quarter of their weight as a six-month-old mouse by the time they were 18 months old, whereas mice on a standard diet gained slightly more than a quarter.
Notably, the extremely restricted mice lived an average of 9 months longer than those on conventional diets, a boost of slightly more than a third.
The averages do not indicate the variation within each of the calorie-controlled groups. While the age distribution within the severely restricted population was far greater than that of their contemporaries, a lot of mice perished at different ages, as if negative factors swamped whatever benefits they could have derived from living on less calories.
In fact, within the calorie-restricted groups it was mice that held onto the most weight that tended to die later, suggesting metabolic regulation is unlikely to explain why calorie-restricted mice lived longer.
Genetics, the authors report, played a far greater role in determining which mice lived to see a ripe old age. Mice that retained weight through stressful handling had a strong chance of living longer, as did those with a greater proportion of infection-fighting white blood cells, and a lower variation in red blood cell size.
Put plainly, a resilient, well-stocked mouse was more likely to survive the rough and tumble of life's pressures and live longer.
It remains unclear why regular fasting or reduced calorie intake helped some mice live longer lives. Without a sure, it is a complicated interaction of elements that appears to be further removed from weight reduction and metabolism than we previously assumed.
Given the probable variations in mouse and human physiology, the findings should make us reconsider our nutrition, health, and lifespan.
That is not to argue that diet restrictions are never appropriate for maintaining a healthy metabolism. Even if our genes have the final say on whether we live to be 99 years old, maintaining excellent health throughout our lives is arguably just as crucial, if not more so.
Source: ScienceAlert
