Study from Palo Alto Medical Foundation Research Institute finds that Punishment May Work for Dieters

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New study finds voluntarily losing money for failing to meet weight-loss goals could help people stay on track for better habits

Depending on your views, having to make a donation to the National Rifle Association, Planned Parenthood or a political party or candidate you do not support may provide motivation to keep exercising and eating healthier over a longer term

Providing financial rewards correlates with more weight lost in studies of weight loss motivation, but what about financial punishment? New findings from the Palo Alto Medical Foundation Research Institute show that people who signed up to lose money for failing to meet specific dieting goals lost more weight. In addition, the greatest weight loss success was among people who signed up to have the money they lost donated to a cause they passionately disagreed with.

“Depending on your views, having to make a donation to the National Rifle Association, Planned Parenthood or a political party or candidate you do not support may provide motivation to keep exercising and eating healthier over a longer term,” explains Harold Luft, Ph.D., director of the Palo Alto Medical Foundation Research Institute and one of the study’s authors.

The study examined 3,857 weight-loss commitment contracts from stickK.com, a site that allows the public to create voluntary personal contracts, with or without a monetary penalty, as a motivation to achieve a specific goal. Anonymity of the participants was protected by having all names removed from the data before the researchers examined it.

The contracts were either penalty or no penalty contracts. In the penalty group, participants had the option of money deducted from a credit card stored on the site either sent to a friend, donated to an organization they agreed with or donated to an organization they disagreed with. Participants whose contracts included penalties were more likely to meet their weight loss goals and more diligent about reporting their weight each week. (Failure to report your weight every seven days resulted in an automatic penalty that week.)

The participants whose penalties went to a group they disagreed with had the best results. In total, 37.1 percent of these participants met their final weight goal compared to 24.1 percent of those whose penalty was set to go to a group or charity they agreed with and 21.1 percent of those whose penalty went to a friend. The no penalty group had the lowest success rate. Only 5.1 percent of these participants met their final weight goal.

The lead author of the study, Lenard Lesser, M.D., MSHS, Clinical Research Lead at One Medical Group, who conducted the research while at Palo Alto Medical Foundation Research Institute, became interested in "commitment contracts" to lose weight when his sister Lori Lesser started using stickK.com.

“As a family doctor, I’ve seen many patients who do not need any more education on eating habits, but need a nudge to avoid all of the food that our society constantly puts in front of people,” explained Lesser.

In addition to being more likely to meet weight loss goals at the end of the contract, Lesser found that those in the penalty group also lost more weight. Weight change per week was -0.33 percent for those whose penalty went to an organization they disagreed with, -0.28 percent for those whose penalty went to an organization they agreed with and -0.25 percent for those whose penalty went to a friend. Larger financial penalties also correlated slightly with more weight lost. Each $10 per week increase in deposit was associated with a -0.1 percent weight change per week.

“On average, for all contracts there was about a -0.39 percent weight loss per week,” Dr. Lesser said. “For a 200-pound male with a contract of 16 weeks, this would be about a 10.5-pound weight loss."

Is it the money or the watcher?

Dr. Lesser cautions that the differences between the groups were significant, but small. He says, “Since there was no control group, the most important component of this intervention may be just setting up a contract where someone watches over you.”

The study found that people who had a person serving as a “referee” or a wireless scale objectively documenting and watching over their progress reported slightly less weight loss. “It is likely that the ‘watcher’ was keeping these people more honest,” Dr. Lesser said.

He was the referee for his sister when she signed up to use StickK.com and advises that people serious about adopting healthy habits should set up a system where they have someone observing their progress. Indeed, this worked for his sister.

“I didn’t put any money down on my contract,” said Lori Lesser. “Just knowing that my brother, a nutrition expert, was watching, helped me keep away from unhealthy foods.”

The study "Association Between Monetary Deposits and Weight Loss in Online Commitment Contracts" by Dr. Lesser, Caroline A. Thompson, Ph.D. and Dr. Luft appears in the American Journal of Health Promotion.

About the Palo Alto Medical Foundation and Sutter Health
The Palo Alto Medical Foundation (PAMF) for Health Care, Research and Education is a not-for-profit health care organization that is a pioneer in the multispecialty group practice of medicine. Founded in 1930, PAMF is part of the Bay Area Region of Sutter Health, one of the nation's leading not-for-profit networks of community-based health care providers. PAMF's nearly 1,500 affiliated physicians and 5,000 employees serve nearly one million patients at 49 medical centers and clinics in Alameda, San Mateo, Santa Clara, Santa Cruz and Contra Costa counties.

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Dean Fryer
California Pacific Medical Center
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