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Fasting every other day doesn't lead to bigger weight loss than daily calorie-cutting and is more difficult to maintain, suggests a University of Illinois at Chicago study published recently in JAMA Internal Medicine. The researchers followed 100 obese people for a year, making this the largest and longest study so far to examine alternate-day fasting.
The alternate-day diet in this study called for participants to take in 25 percent of their needed calories on fast days and 125 percent on feast days. It's a type of intermittent fasting that involves drastically reducing your calorie intake on some days or during certain hours and eating whatever you like on others. The theory is that it is easier to focus on reducing calorie intake only some of the time and that the eating pattern improves cardiovascular risk factors — such as blood pressure, cholesterol and insulin levels — more than daily calorie-cutting does.
In this study, those who took the intermittent-fasting approach lost the same amount of weight, on average, as those who cut back on calories — to 75 percent of their needs — every day. Both groups dropped about 7 percent of their body weight after six months and regained about 1 percent of their weight during the six-month weight-maintenance phase.
"We can say that alternate-day fasting does produce clinically significant weight loss after a year, but it's not better than a typical calorie-restricted diet," says study researcher Krista A. Varady, an associate professor of nutrition at the University of Illinois at Chicago.
This eating style also appears to be difficult to stick to, she says. Thirty-eight percent of the alternate-day fasters dropped out, compared with 29 percent of the regular dieters. And about half of the alternate-day group ended up consuming more calories than planned on fasting days and fewer on feast days, so they essentially followed the same plan as the regular dieters.
Cardiovascular disease risk factors, which usually improve with weight loss, were similar in both groups, with two exceptions: "Bad" cholesterol (low-density lipoprotein, or LDL) levels were significantly higher in the fasters after a year. But, Varady says, "we did have a subgroup of people who had pre-diabetes, and they saw bigger improvements in insulin resistance, inflammatory factors and triglyceride levels with alternate-day fasting."
So, how to know which approach to weight loss is best for you? "They can all work," says Marie-Pierre St-Onge, an associate professor of nutritional medicine at Columbia University in New York City. "If it's a diet that helps you feel full and less deprived, and it's something you can adhere to, you should be able to lose weight."
Here, five strategies to help:
● Determine what suits your lifestyle and preferences. Alternate-day fasting may be a good plan for some. "It doesn't work well with people who are frequent snackers, but those who routinely go five or six hours without eating tend to do well with it," Varady says.
● Eat more veggies and fruits. In addition to being packed with nutrients, produce adds bulk to your plate, so you feel as if you're eating more food.
● Know your triggers. "Be aware of when, where and why you're susceptible to overeating," St-Onge says. "We eat for so many reasons other than hunger, so stop and ask yourself why you want to eat right now."
● Avoid high-calorie drinks. Sugary beverages such as sodas, juices and sweetened coffee drinks don't register in the brain the same way solid foods do, so you end up eating more, St-Onge says.
● Front-load meals. Research published in the American Journal of Clinical Nutrition found that obese women who took in half their daily calories at lunch lost three pounds more than those who ate most of their calories during dinner over the 12-week study period.
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