Have real fun,

make real change.

Games that power the changes you
want to make in your life. It’s the better way
to lose weight—find out why.

Lost 25 lbs

Won $500

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About DietBet

Launched in 2013, DietBet is the first product from WayBetter™, a company that makes games that help people achieve their goals.

To help people achieve their weight-loss goals, DietBet employs the principles of The WayBetter Way™:

  • Commitment with real financial accountability and concrete goals.
  • Community support to keep you laughing and lift you up with you fall.
  • Celebrations for success with real rewards that make it more fun and keep you on track.
Dietbetting works: 97% of players lose weight. Our library of testimonials is just a sampling of the enthusiastic players who are living, breathing success stories. Winners in short-term dietbets (Kickstarters) lose an average of nine pounds a month, and winners in our long-term dietbets (Transformers) lose an average of 24 pounds after six months. Since its launch, players have lost a combined 3.6 million pounds through dietbets. Along the way, WayBetter has paid out over $16 million to winners. A new format to help players maintain their weight after they’ve reached their goal weight is planned for release in early 2016.

DietBet is based on scientific principles of behavioral economics and has underpinnings in research from the University of Pennsylvania and the Mayo Clinic. DietBet was the subject of a journal article by Brown Medical School that won the Obesity Society’s eHealth award.

DietBet is more than a game. It is a fast-growing movement around the world with over 300,000 players in 100+ countries. Today, hundreds of health and wellness experts regularly lead their fans in dietbets. Game hosts include celebrity trainers Jillian Michaels, Chris Powell and Shaun T, and leading health brands like Withings, Runkeeper, and Fitness Magazine. The biggest dietbet to date was recently led by Chris & Heidi Powell (of ABC’s Extreme Weight Loss) with a pot of $366,060.

DietBet's Founder & CEO

Jamie Rosen, Founder & CEO, dropped out of Harvard Business School to start his first internet business, Comet Systems, which he sold in 2004 for $33.5 million. At Comet, he invented the company's flagship product, which won Adweek's "Best Marketing Technology of the Year" award in 1999. That same year he was profiled as CNBC's "Entrepreneur of the Week." Prior to Comet, Rosen was a toy inventor and today he has 10 pending and issued patents. In 2007, he sold several of his patents, covering location-based games, to Yahoo! He graduated from Harvard College in 1992 and is married with three children.


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DietBet Fact Sheet

  • Getting Started. Players can set up a game with friends or join a public game. Hundreds of authors, bloggers, and celebrities regularly lead dietbets with their fans.
  • The Kickstarter vs. the Transformer vs. the Maintainer. These are our three dietbet formats. The Kickstarter is a 4-week game to lose 4% of your starting weight. This short-term dietbet is designed to motivate people to begin their weight loss journey, power through a weight plateau, or get in shape for a special event. The Transformer is our 6-month game to lose 10% of your starting weight (with interim goals and prizes along the way). This longer-term dietbet is designed to help players lose weight gradually while making behavior changes that they can sustain. We chose this goal because 10% has been shown to dramatically reduce the risk of cardiovascular disease and type-2 diabetes in overweight individuals. The Maintainer is our 12-month game to maintain your weight, with a 2% allowance for fluctuations in either direction. This dietbet is designed for players who have achieved their weight loss goals through Kickstarters or Transformers and want a structured and supportive way to keep it off. The game is 12 months because research has shown that people are more likely to maintain weight loss over the long-term if they keep it off for one year.
  • Verifying Weights to Prevent Cheating All players must go through official weigh-ins at the start and end of each game (weigh-in windows open for 48 hours at both ends). This typically entails taking and submitting two photos in accordance with DietBet’s weigh-in guidelines. The first photo must show the player, head-to-toe, in “lightweight clothing” (pockets empty, no shoes or outerwear). The second shows the scale’s weight alongside a “weigh-in word” written on an index card. Weigh-in words are provided to players at the time of the weigh-in and serve as a timestamp to ensure that photos are not used in multiple games. DietBet’s human Referees carefully review and approve all weigh-ins confidentially. DietBet regularly audits players and requires some players to conduct weigh-ins using uncut videos instead of photos. In some cases, players must weigh-in with Referees via Skype.
  • Privacy. Players’ weights are kept private by default though players may elect to reveal their weights to other players in the game. Weigh-in photos are always kept private.
  • Unofficial Weigh-ins. Players are encouraged to post their weights regularly during the game to track their progress and to update their charts. Only official weigh-ins, verified by DietBet's Referees, are used to determine the winners.
  • Mobile App. Android and iOS apps let players conveniently interact with other players, update their weights, and post photos. The apps also facilitate official weigh-ins. Push notifications remind players of upcoming deadlines. In addition, players can connect to other popular apps such as RunKeeper, MapMyFitness, Jawbone, Withings, and Fitbit.
  • Rules. DietBet has a comprehensive set of rules which cover everything from what to wear at weigh-ins to what happens if everyone reaches the goal (in this case, our “no-lose guarantee” kicks in - DietBet forgoes its cut and players all get their money back).
  • How DietBet Makes Money. DietBet keeps a cut of the pot to cover transaction costs (normally credit card in and Paypal out), Refereeing, and fees to game hosts. DietBet’s cut ranges from 10-25% depending on the bet size.
  • Safe Weight-Loss. DietBet games are designed to facilitate safe and sustainable weight-loss. For starters, the game is not about losing the most weight. Everyone who reaches his or her weight target is declared a winner and splits the pot evenly with all the other winners, with no extra credit for losing the most (or for losing weight the fastest). We punish extreme weight loss as players who lose too much are immediately disqualified (more than 3x the target). And players who do not have a healthy amount of weight to lose may not play in the first place - to join, your BMI at your goal weight must be over 18.5. (Below 18.5 is considered underweight by the National Institute of Health). Finally, you must be at least 18 years old to play.
  • Global. DietBet supports pounds and kilograms and is available around the world. We have had players from more than 70 countries.
  • Why Is This Legal? DietBetting is a game of skill, with no luck involved. As such it is not regulated as gambling.