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By Stephanie Stahl

PHILADELPHIA (CBS) — Losing and gaining weight is a weekly cycle for most people, according to new research that reveals a pattern for slim success.  3 On Your Side Health Reporter Stephanie Stahl explains.

What’s your weekend indulgence?  Pizza, a couple of extra drinks or homemade sweet treats?  New research from Cornell University confirms weekend pig outs are common.

“Every person in the world ends up weighing more Sunday night,” said Professor Brian Wansink, who wrote the book “Slim By Design” and conducted the Cornell study.  It found there are weekly weight cycles.  People tend to gain weight over the weekend then lose it during the week.

“It doesn’t matter whether you’re really skinny individual or real heavy individual there’s a definite rhythm to weight,” said Wansink.

The research found successful dieters were able to steadily lose weight on weekdays, reaching a low on Friday.

“The biggest thing that actually differentiated between whether people lost weight or gained weight over the entire course of the year was how much they lost during the week,” said Wansink.

People who gained weight, according to the research, had more variability, and no clear loss through the week.

“Based on our study, if you want to be slim don’t worry what happens on the weekend.  Worry what happens during the week,” said Wansink.

The study followed 80 adults for a year.  Researchers say the results indicate that quick splurges on the weekend are okay, as long as people get right back to their diet routine.

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