Fontana was unconvinced, but curious. “I’m a scientist, so I’m always skeptical…unless you do research on humans.”
he did. To test whether intermittent fasting had an effect beyond weight loss, he and his team randomly divided his 50 overweight participants into two groups.
For six months, one group ate a typical Western diet for four to five days, followed by a vegetable fast for two to three days. Most recently, they didn’t count kilojoules, but ate only non-starchy vegetables drizzled with two tablespoons of olive oil and either vinegar or lemon. continued to eat.
The researchers tested for key markers of healthy aging, including inflammation, insulin sensitivity, mTOR (a protein that helps control important cell functions), and autophagy activation (a process that removes cellular damage).
After 6 months, participants in the intermittent fasting group lost about 8% of their body weight (up to 20 kilograms) and 16% of their body fat. It did not reduce glucose tolerance or insulin sensitivity.
“Yes, they lose weight. They lose fat. says Fontana, the author of the book. The Longevity and Happiness Manual: A 3-Step Plan.
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“Inflammation is a major factor in aging, cancer and cardiovascular disease…inflammation and insulin sensitivity are the most important factors in aging biology.”
These findings show that weight loss per se is no guarantee of good health, and Fontana adds that the study confirms that kilojoules are not kilojoules. What you eat matters.
“The short cut, ‘You can lose weight by fasting two days a week, and then you’ll be healthy, and you can do whatever you want for five days,’ is wrong,” he stresses. “The quality of food eaten on non-fasting days and the amount of physical activity on non-fasting days profoundly influence the metabolic response to weight loss.”
Evelyn Parr, Ph.D., a research fellow at the Mary McKillop Institute for Health Research at the Catholic University of Australia, wondered if there were enough levels of inflammation to produce significant changes across cohorts.
“If intermittent fasting allows someone to control their weekly energy intake and adhere to their dietary energy intake for weight maintenance, I’m all for it,” says Parr. If not, we believe that alternative strategies such as time-restricted eating (TRE) and chronic energy restriction (i.e. smaller daily limits) would be better approaches, as approaches that may increase adherence. is more likely to promote eating more… health benefits.”
However, as Fontana discovered, it is possible to overdo it. In some participants, researchers performed colonic biopsies and found that excessive weight loss from intermittent fasting compromised anti-aging pathways.
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Fontana, who doesn’t fast or count calories but does pay attention to the quality of his diet, says the study refutes the notion that fasting a few days a week allows you to eat and drink as much as you want. .
“The quality of your diet is important. There are many other factors in the quality of exercise, the amount of exercise and the longevity path that are part of this puzzle.”
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