Banish the pre-vacation diet

Cutting calories three days in a row will backfire.

Everyone wants to look and feel their best for a big trip or event, but crash-dieting for a few days beforehand is not the answer, according to a new study.

For a new study, researchers reduced female rats’ diets from the human equivalent of 2,000 to 800 calories per day for three days. The rats lost weight initially but regained it as soon as they started eating normally again. More importantly, the dieters had significantly more abdominal fat three months later than the other rats did. The team is studying whether extreme diets of this length have similar effects on males.

It’s not that pre-vacation detoxes are a sign of unhealthy, inconsistent eating patterns. Physiologically, crash-dieting for a few days in a row actually has long-term effects on fat metabolism and where fat accumulates in the body, says principal investigator Kathryn Sandberg, Ph.D., director of the Center for the Study of Sex Differences in Health, Aging and Disease at Georgetown University in Washington, D.C.

Anytime you restrict your calorie intake by 1,000 calories (or about 60 percent) or more, it’s considered a crash diet. That’s different from fasting, or abstaining from food completely, on alternate days or for just 24 hours at a time.

“Physiology does not care about your high school reunion,” Sandberg says. If your goal is to lose a few pounds before a big vacation or event, start earlier and never reduce your intake by more than 500 calories for three or more days in a row.