Diets suffer big-time on weekends

July 30, 2008 8:39:31 AM PDT
If you are trying to lose weight, better tighten the reigns on what you eat on Saturdays!

The song calls Saturday night "the loneliest night of the week." It's also the roughest for those trying to curb their calories.

Researchers have some science to back up dieters' complaints about weekends being their undoing: Most people DO eat more on the weekend, even when they're trying to lose weight.

"Weekend indulgences can wreak havoc on weight control, either causing our weight to increase or if we are following a diet to lose weight, can hinder our weight loss efforts," said study author Susan Racette, an assistant professor at Washington University in St. Louis. The research was published online recently in the journal Obesity.

Racette and her colleagues followed 48 men and women for a year, trying to determine the effects of weekends on weight loss efforts. All of them kept food diaries, and wore devices to help them measure their activity.

Even before the project started, information Racette gathered on the volunteers eating and exercise habits indicated weekends were the time to eat more, and be less active.

"Before they were supposed to be following a diet or exercise plan, we found on weekends, people gained weight," she said. During the week, the weight would decline. But the weekend effect was strong. "If you translate it out to a year, it could have increased weight by 9 pounds."

Before the intervention, participants ate an average of 2,257 calories on Saturday compared to just 2,021 during the week. But the average activity on weekends overall didn't differ much from average weekday activities. So, it was the food, not the lack of activity, that was to blame, Racette said.

Racette monitored the participants for a year after they started the intervention, and the weekend indulgences continued. The calorie restriction group stopped losing weight on weekends, while the physical activity group gained slightly (about .17 pounds). There were not significant weight changes in the controls on weekends.

Weekend indulgences help explain the slower-than-expected weight loss of many dieters, Racette said. "There is less structure on the weekend for a lot of people, and that can wreak havoc," she said. "A little indulgence turns into a big indulgence. Being vigilant on the weekends is really important for people either trying to lose weight or maintain a weight loss," she said.