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Intermittent dieting helps weight loss: Experts explore fasting pros and cons

Should you fast?
Should you fast?
Photo by Theo Wargo

The popularity of intermittent fasting has skyrocketed in recent years. Now a researcher has found that using that principle with dieting results in the same amount of weight loss as continuous dieting, reported Medical Research News on July 23.

Jennifer Keogh, Associate Professor of Dietetics and Nutrition at the University of South Australia, studied two groups of dieters. One group followed a weight loss plan for eight weeks. The other group alternated one week of dieting with one week of normal eating.

"The main finding was that weight loss was not significantly different between the two groups after eight weeks," said Keogh. At the end of a year, the same results occurred.

"The findings were consistent with our hypothesis that that those on the intermittent energy restriction would achieve comparable weight loss and weight loss maintenance at 12 months compared to those on the continuous diet," said the professor. She advises those who struggle with dieting to consider using the intermittent dieting approach.

As for intermittent fasting, which involves restricting calories just two days a week, the plan sometimes called the 5:2 diet has been shown to be effective for weight loss. But complete fasts, without food or drink, could cause problems, reported NBC News on July 24.

For those fasting for religious reasons, abstinence from water and food may be required from dawn until dusk. The spiritual benefits among those who practice those religions are clear. But how is the body impacted?

One study discovered that those who regularly fast reduce their risk of heart disease. Another study showed reductions in blood sugar levels and bad cholesterol. But does it work for weight loss?

"Fasting should never be undertaken to lose weight," says nutritionist Adam Brown. However, "some weight loss is reported by most people who fast."

The lack of water during fasting in Ramadan does cause some dehydration, according to a study conducted by researchers from Aberdeen University and Kuwait University. They found "increased irritability and incidences of headaches with sleep deprivation and lassitude prevalent." However, they discovered no negative impact on health "directly attributed to negative water balance at the levels that may be produced during Ramadan."

In contrast to such fasts, intermittent fasting based on alternate days of restricted calories allow unlimited amounts of water. And some nutritionists and other diet experts feel that the intermittent fasting approach is helpful for weight loss.

"In terms of dieting, intermittent fasting is another form of self-discipline," said Jo Ann Hattner, a registered dietitian and nutrition consultant to the Stanford University School of Medicine, in a San Francisco Chronicle interview. "The bottom line is that Americans are gaining weight because they eat too many calories, and, like passing on seconds at dinner, it's a way to teach the body it doesn't need so much food."

A variety of studies have been conducted to determine the benefits of intermittent fasting. Among the proponents are Paleo diet guru Mark Sisson, who notes that this approach mimics the eating style of our caveman (and cavewomen) ancestors.