The case for fasting diets just got a little bit stronger.
A just-released study by researchers at Johns Hopkins University indicates that such diets not only help you lose weight but will also improve your metabolism.
“We are at a transition point where we could soon consider adding information about intermittent fasting to medical school curricula alongside standard advice about healthy diets and exercise,” Professor Mattson, who directed the study, says.
There are various kinds of fasting or “intermittent” diets, depending on how one’s food intake is restricted. In some of the diets, the participants don’t eat at all for two days out of the week. In others, they eat in spurts.
Past studies have suggested that fasting diets can lead to decreased blood pressure, cholesterol and resting heart rates. They can also help control blood sugar levels, increase resistance to stress and suppress inflammation.
The newest study suggests that fast dieting works through a process known as “metabolic switching” in which cells use up their fuel stores and convert fat to energy — “flipping a switch” from fat-storing to fat-saving.
Metabolic switching can also increase resistance to stress by optimizing brain function and neuroplasticity, or the brain’s ability to adapt to develop throughout one’s life, according to a previous Mattson study. Also, older adults on a fast diet have been shown to improve their verbal memory compared to two other groups who hadn’t fasted.
There is even some evidence that intermittent fasting has a special effect on diabetes. In a 2018 study, three diabetic men were able to stop taking insulin after losing weight from intermittent fasting — a result that challenges the widely-held belief that diabetes is incurable.
Experts warn than while promising, the latest research results require further validation. The sample sizes were small and participants tended to be younger men and middle-aged men, largely White, and male. More experiments are needed with a more diverse array of sub-groups.
In addition, fasting diets are demanding and not broadly popular. Some leading celebrities, including Kourtney Kardashian, have extolled their virtues but many everyday consumers find them hard to stick to.
The reason? In America’s deeply ingrained three-meals-a-day culture, many people have a hard time adjusting to the fasting, which can leave them feeling hungry, irritable and unable to concentrate.
In a 2017 study, almost 40% of people who were assigned to a fasting diet dropped out before the study ended, citing health and behavioral concerns.
Moreover, some fasting diets can cause their participants to engage in over-eating during non-fasting days, to compensate for the reduced food intake during the fasting period. Instead of weight loss, bloating occurs
More research is also needed on which if any of the intermittent fasts might be most effective — and with whom.
The most common fasting diet is one in which food intake occurs within a 6-hour window after which the person fasts for the next 18 hours. The other major variant is the 5:2 diet which allows normal eating for 5 days followed by two days with only 500 calories per day allowed.
One of the issues that often gets lost in the discussion is the quality of the faster’s diet as well as the need for exercise. If unhealthy eating persists, the fasting benefits will be reduced. And some people feel less inclined to exercise, especially during the fasting periods, another potential mitigating factor.
Some researchers are holding out hope that a pharmacological alternative to intermittent fasting may soon be available.
In tests with animals, an experimental pill has shown signs of inducing the same metabolic processes as intermittent fasting.
But skeptics say the safety and efficacy of a pharmacological approach have yet to be demonstrated — even in animal subjects. And its prospective benefits are likely to be much weaker than those obtained by carefully managing one’s food intake, they argue.
For all of these reasons, intermittent fasting in one form or another could well become the dieting wave of the future.