Fasting for 24 hours between meals could lower diabetes risk
Eating only once a day could reduce inflammation associated with diseases such as Alzheimer’s and Parkinson’s, study suggests.
Regular periods of fasting where you leave 24 hours between meals could reduce your risk of diseases such as diabetes and Alzheimer’s, a Cambridge study suggests.
Researchers have found that leaving a full day between meals can reduce levels of harmful inflammation in the body by boosting production of a key fatty acid, suggesting that routine fasting sessions could boost your health.
Fasting diets have grown in popularity in recent years, with claims that they are effective as a means of weight loss, as a way of keeping the body’s cells healthy, and even as a way of boosting productivity.
It emerged this week that the prime minister, Rishi Sunak, fasts for 36 hours at the start of every week as part of a “balanced lifestyle”, arguing that it then allows him to indulge his “weakness for sugary things” for the rest of the week.
It has long been suspected that the human body is not well suited, in evolutionary terms, to the modern habit of constant snacking and grazing throughout the day. Instead, it is thought that our bodies are better adapted to the dietary routine of our hunter-gatherer ancestors, who were likely to have eaten fewer meals with much longer gaps in between.
Scientists suspect that leaving longer gaps between meals gives our bodies time to perform the repair and maintenance tasks that keep our cells healthy. It is thought that these processes are interrupted or weakened if we are constantly topping up our blood sugar by snacking.
When the body’s immune system is triggered into action, it kickstarts a process known as inflammation, where the body prepares to defend itself and repair damage. But extended periods of inflammation are thought to be harmful and have been linked with a number of conditions and diseases.
“We’re very interested in trying to understand the causes of chronic inflammation in the context of many human diseases, and in particular the role of the inflammasome [molecules that activate inflammatory responses],” said Clare Bryant from Cambridge’s department of medicine.
“What’s become apparent over recent years is that one inflammasome in particular — the NLRP3 inflammasome — is very important in a number of major diseases such as obesity and atherosclerosis, but also in diseases like Alzheimer’s and Parkinson’s diseases, many of the diseases of older-age people, particularly in the western world.”
Scientists wanted to find out why fasting seems to reduce inflammation. They studied a group of 21 volunteers, asking them to eat a 500-calorie meal, fast for 24 hours, and then eat another 500-calorie meal.
The results, published in the journal Cell Reports, found that this 24-hour fast increased the levels of a fatty acid called arachidonic acid. These levels then dropped again once the participants ate another meal.
The researchers tested the effect of this acid on immune cells in a laboratory and found that arachidonic acid reduced the activity of the NLRP3 inflammasome linked with harmful inflammation.
“This provides a potential explanation for how changing our diet — in particular by fasting — protects us from inflammation, especially the damaging form that underpins many diseases related to a western high-calorie diet,” Bryant said.
“It’s too early to say whether fasting protects against diseases like Alzheimer’s and Parkinson’s disease as the effects of arachidonic acid are only short-lived, but our work adds to a growing amount of scientific literature that points to the health benefits of calorie restriction.
“It suggests that regular fasting over a long period could help reduce the chronic inflammation we associate with these conditions. It’s certainly an attractive idea.”
Scientists remain divided on the benefits of fasting diets, however. Animal studies conducted on zebrafish suggest that fasting may affect fertility, but researchers at the University of Illinois Chicago have so far found no evidence of this in humans.
The study may also have uncovered how drugs such as aspirin work, suggesting that aspirin might prevent or slow the breakdown of arachidonic acid, giving it time to do its work in reducing inflammation.
Bryant warned, however, that aspirin should not be taken to reduce the risk of long-term diseases without medical advice, as prolonged use can harm the stomach.
She added that further studies would be needed to ascertain how regularly it would be safe and beneficial to undertake 24-hour fasting periods, noting: “That’s a question for future work and it’s a good one too. I am super interested to know the answer.”
The Times
