Studies suggest that reducing calories may rejuvenate.
Researchers studied 220 people, one-third of whom cut their calorie intake by 25% over two years, while the rest ate normally.
Those who cut calories appeared to age up to 3% more slowly. The authors argue that this could reduce the risk of early death as much as quitting smoking.
It is well known that reducing calories makes obese people healthier by losing weight. However, this is the first long-term study of calorie reduction in healthy, nonobese people.
This supports previous studies in mice and rats that have shown that one of the best ways to achieve the Holy Grail of longer, healthier lives is to cut calories.
A state-of-the-art blood test developed over the past decade has been used to slow the rate of aging in dieters.
The test was developed using signs of aging, such as high blood pressure and cholesterol, tracked in hundreds of people between the ages of 26 and 45.
These signs of aging were consistent with genetic activity in the body. Using this gene activity alone, a final blood test determined how fast people were aging.
“This study is very exciting because it finds that caloric restriction can biologically slow the pace of aging,” said Daniel Belsky, Ph.D., who led the study at Columbia University’s Mailman School of Public Health in New York. .
“Delaying biological aging means living longer and getting sick later.
“Therefore, calorie restriction may not only lead obese people to live longer and healthier lives, but also healthy people.”
The study, published in the journal Nature Aging, looked at people in New Zealand who had been helped by a previous study to cut calories with weekly weight loss sessions.
Volunteers started on the small meals provided for 27 days and then continued the diet alone, typically losing 15% of their body weight in the first year.
Not everyone hits the goal of reducing calories by 25%.
However, an analysis of the dieting group as a whole found that they aged 2-3% slower than those who ate normally.
Those who cut their calorie intake by 10% or more benefited the most, aging about 1% slower than those who cut their calorie intake by less.
This study used three tests of biological age. All of these look at a genetic activity called DNA methylation. This is an ‘epigenetic’ change in the cell that acts like a dimmer switch to turn gene activity up and down.
DNA methylation in blood cells from blood tests indicates whether people are aging at a normal rate and may indicate signs of aging such as elevated blood pressure and decreased effectiveness of the immune system.
Calorie cutting was only found to be beneficial using one of the DunedinPACE tests of biological aging.
The study authors say this is because two of the tests are snapshots of biological age, rather than measuring people’s rate of aging over time.
Previous research suggests that slowing aging by 2-3% reduces the risk of premature death by 10-15%.
Therefore, the authors say, a two-year calorie-cutting diet may have the same effect on someone’s risk of early death as seen in studies of people who quit smoking.
“Calorie restriction probably isn’t for everyone,” said Karen Ryan, M.D., of Columbia University’s Mailman School of Public Health, co-lead author of the study. This is important because it provides evidence from randomized trials that it may be possible.
“They also give us a sense of the kinds of effects we might look for in trials of interventions that could appeal to a wider range of people, such as intermittent fasting and timed diets.”
Follow-up studies of trial participants are currently underway to determine whether people on a low-calorie diet can actually live longer, healthier lives, as blood tests suggest.
