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Yo-yo dieting in mice shows longevity benefit in controversial new study

New obesity research conducted in mice suggests that yo-yo dieting does not damage the metabolism and may even increase lifespan.
Dr David Alliso, from the University of Alabama in Birmingham, USA, found that obese mice repeatedly placed on crash diets – presumably involving some degree of calorie restriction – lived longer than mice maintaining a normal diet.
We know from previous research in rhesus monkeys that there are significant longevity benefits to long-term sustained calorie restriction.
Compared to monkeys on a calorie-restricted diet for 20+ years, monkeys on a normal diet had a 2.9 times increased risk of disease, and a threefold increased risk of death.
But, these monkeys were maintained on a single diet throughout their lives. And until now, it was unclear whether some of these findings held true with periodic (yo-yo) dieting.
Allison’s research tends to support that theory, at least in rodents, but created controversy among health experts about its applicability to humans.
Professor Tim Spector, from King’s College London, reacted strongly against Allison’s claim that periodic dieting isn’t going to be damaging to the metabolism.
“Data in humans shows that yo-yo dieting makes you gain weight long-term. In our twin study of 5,000 twins, the yo-yo dieter was usually heavier long-term than the identical twin who didn’t diet,” Spector told the Press Association.
Microbiologists also raised some concerns about the effect of periodic dieting on gut health. Israeli researchers recently found in mice that yo-yo dieting led to a massive change in the gut microbiome.
The new population of gut microbes permanently altered energy balance and, when transplanted into healthy mice, made them obese.
One thing that experts could, however, rally around, is the idea that losing weight can go a long way towards improving long-term health outcomes.
It is estimated that around two in three British adults have body mass indexes (BMIs) that classify them as overweight or obese.
“It’s probably not a bad idea to lose weight even if you are going to gain it back and redo it every few years,” Allison said, speaking at the American Association for the Advancement of Science (AAAS) annual meeting in Bosto, Massachusetts.

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