Dec. 26 (UPI) -- Want to live longer? Think fast.
Or, more precisely, fasting. A review of existing studies published Thursday in the New England Journal of Medicine suggests that periodically forgoing meals can improve overall health by helping regulate blood sugar levels, improving the body's resistance to stress and suppressing inflammation.
"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," co-author Mark Mattson, a neuroscientist at Johns Hopkins Medicine, said in a statement.
Mattson has been practicing so-called "intermittent fasting" for more than 20 years. He said he wrote the article to clarify the science surrounding fasting to help physicians guide patients who want to try it.
Studies in animals and people have shown that alternating between times of fasting and eating supports cellular health, likely by triggering an age-old adaptation to periods of food scarcity called metabolic switching. Metabolic switching occurs when cells use up their stores of rapidly accessible, sugar-based fuel and begin converting fat into energy.
Because most Americans eat three meals plus snacks each day, Mattson noted, they do not experience metabolic switching, or its potential benefits.
According to Mattson, intermittent fasting diets fall into two categories: daily time-restricted feeding, which narrows eating times to six to eight hours per day; and "5:2" intermittent fasting, in which people limit themselves to one moderate-size meal two days per week. His article cites four studies that found that intermittent fasting decreased blood pressure, blood lipid levels and resting heart rates.
Evidence also suggests that intermittent fasting can help reduce risk for obesity and diabetes. Two studies at the University Hospital of South Manchester NHS Foundation Trust, for example, showed that overweight women on the 5:2 intermittent fasting diet lost the same amount of weight as women who restricted calories, but did better on measures of insulin sensitivity and reduced belly fat.
In addition, Mattson said studies have indicated that intermittent fasting may benefit brain health.
A multicenter clinical trial at the University of Toronto in April, for example, found that 220 healthy, non-obese adults who maintained a calorie restricted diet for two years showed signs of improved memory in cognitive tests. While far more research is needed, these findings suggest intermittent fasting may help stave off neuro-degeneration and dementia.
Although not everyone is willing or able to adhere to fasting regimens, Mattson argues that, with guidance and patience, most people can incorporate them into their lives -- even though it takes some time for the body to adjust and overcome initial hunger pangs and irritability.
To manage this, Mattson recommends that physicians advise patients to gradually increase the duration and frequency of the fasting periods over the course of several months, instead of "going cold turkey."
He added that "patients should be advised that feeling hungry and irritable is common initially and usually passes after two weeks to a month as the body and brain become accustomed to the new habit."