Cindy wanted to lose weight. She knew just what to do: eat less and exercise more. She knew all about the food pyramid and the hidden calories in soft drinks. Still, nothing had worked. She had gained forty pounds with the birth of her second child and it just wasn’t coming off. That’s why she accepted ABC’s offer to help her lose weight. On December 9th, she came into a photographer’s studio on Manhattan’s West Side where she found herself in changing into a bikini. She hadn’t worn a bikini since she was nine and this wasn’t the time to start again. The setup felt like backstage at the Sports Illustrated swimsuit issue. There were lights and cameras everywhere and all she had on was a tiny lime-green bikini. The producers had thoughtfully placed a hidden space heater to keep her warm. Snap. Smile. Snap. Smile. What in the world was she thinking? Snap. If things worked out as she hoped, no one would ever see these pictures. The deal she made with ABC Primetime is that they would destroy the pictures if she lost 15 pounds over the next two months. They wouldn’t help her in any way. No coach, no trainer, no special diets. She already knew what she had to do. All she needed was some extra motivation and a reason to start today rather than tomorrow. Now she had that extra motivation. If she didn’t lose the promised weight, ABC would show the photos and the videos on primetime television. She had already signed the release giving them permission. Fifteen pounds in two months was a safe amount to lose, but it wouldn’t be a cakewalk. There was a series of holiday parties and Christmas dinners. She couldn’t risk waiting until the New Year. She was starting as of now. Cindy knew all about the dangers of being overweight—the increased risk of diabetes, heart attack, and death. And yet that wasn’t enough to scare her into action. What she feared more that anything was the possibility that her ex-boyfriend would see her hanging out of a bikini on national TV. And there was little doubt that he would watch the show. Her best friend was going to tell him if she failed. Laurie didn’t like the way she looked or how she felt. It didn’t help that she worked part-time tending bar, surrounded by 20-year-old hotties. She had tried Weight-Watchers, South Beach, Slim Fast, you name it. She was headed in the wrong direction and needed something to help her change course. When she told her girlfriends about the show, they thought it was the stupidest thing she’d ever done. The cameras captured that “what am I doing?” look on her face and lots more. Ray needed to lose weight, too. He was a newlywed in his twenties, but looked closer to forty. As the walked the red carpet in his racing swimsuit, it wasn’t a pretty sight. Click. Smile. Click. Ray wasn’t taking any chances. His wife wanted him to lose weight and was willing to help. She offered to diet with him. Then she took the plunge. She changed into a bikini, too. She wasn’t as overweight as Frank, but she wasn’t bikini-ready either. Her deal was different from Cindy’s. She didn’t have to weigh in. She didn’t even have to lose weight. The pictures of her in a bikini would only be shown if Ray didn’t lose the weight. Ray had raised the stakes even higher. He was either going to lose the weight or his wife. All together, four women and one couple bared their soles and plenty more in front of the cameras. What they were doing? They weren’t exhibitionists. The ABC producers had carefully screened out them out. None of the five wanted to see these photos appear on TV and none of them expected they ever would. They were playing a game against their future selves. Today’s self wants the future self to diet and exercise. The future self wants the ice cream and the television. Most of the time, the future self wins because it gets to move last. The trick is to change the incentives for the future self so as to change its behavior. In Greek mythology, Ulysses wanted to hear the sirens’ songs. He knew that if he allowed his future self to listen to their song, that future self would sail his ship into the rocks. So he tied his hands—literally. He had his crew bind his hands to the mast (while plugging their own ears). In dieting, this is known as the empty-fridge strategy. Cindy, Laurie, and Ray went one step further. They put themselves in a bind that only dieting would get them out of. You might think that having more options is always a good thing. But thinking strategically, you can often do better by cutting off options. Nobel-prize economist Tom Schelling describes how the Athenian General Xenophon fought with his back against an impassible ravine. He purposefully set himself up so that his soldiers had no option of retreat. Backs stiffened, they won. Similarly, Cortès scuttled his ships upon arrival in Mexico. This decision was made with the support of his troops. Vastly outnumbered, his six hundred soldiers decided that they would either defeat the Aztecs or perish trying. The Aztecs could retreat inland, but for Cortès’s soldiers there was no possibility of desertion or retreat. By making defeat worse, Cortès increased his chance of victory and indeed conquered. What worked for Cortès and Xenophon worked for Cindy, Laurie, Ray and the rest. Two months later, just in time for Valentines Day, Cindy had lost 17 pounds. Ray was down 22 pounds and two belt loops. While the threat was the motivator to get them started, once they got going, they were doing it for themselves. Laurie lost the required 15 pounds in the first month. She kept on going and lost another 13 in month two. Laurie’s 28 pounds translated into two dress sizes and over 14% of her body weight. Her friends no longer think the ABC show was a stupid idea. Perhaps, we should have called this book Thinning Strategically and sold many more copies.  See Thomas Schelling, Arms and Influence, p. 43 and Xenophon, The Persian Expedition, pp. 136—37, 236.  In The Art of War, Sun Tzu emphasizes that the attacking army should always provide an escape route to the adversary, so as to prevent them from fighting with the strength of desperation. Then in a footnote, he suggests that the retreating army should be ambushed. That, of course, only works if the opposing army hasn’t read Sun Tzu.  Cortès was also helped by the misconception that he was Quetzaquotal, a fair-skinned Aztec god.