Want to Lose Weight This Year? Choose the Right Resolution

A behavioral economist explains why a resolution to lose weight is a bad idea, and suggests something better

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Once upon a time (in January 2013 to be precise), my friend Alex decided he needed a change. In the 17 years since he’d gotten married, he had gained a pound a year. He had slowly but surely become an overweight middle-aged man, and enough was finally enough. Like millions of other Americans, he decided to start the New Year with a diet. His physician couldn’t agree more — Alex needed to lose weight.

Alex was upbeat and optimistic about his New Year’s resolution. His goal was to lose a pound a week. Something hard yet doable.

The first week of January, he skipped the sweets and after-dinner whiskey, and he joined a gym. The experts suggested he should weigh himself only once a week. You can imagine how happy he was when the scale showed he had lost 2 lb. during the first week. He almost felt two years younger. The next week he lost 1 lb. The end of the third week marked a turning point: Alex was traveling and couldn’t keep up with his new habits, which resulted in a gain of a pound. You can probably figure out where this is going.

Today, a year later, Alex weighs 18 lb. more than he did when he got married. He is still an overweight middle-aged man.

Millions of Americans will kick off 2014 with the same resolution they started 2013 with — a goal of losing weight. Some will succeed, but only a handful will keep the weight off in the long run. Why? Because losing weight is the wrong goal. Don’t misunderstand me. Many of us could benefit from losing a little weight. Defining weight loss as a goal, however, is a mistake.

(MORE: Q&A: Willpower Expert Roy Baumeister on Staying in Control)

To reach our goal of losing weight (the “output”), we need to control what we eat (the “input”). That is, we tend to care about the output but control the input. This is a bad way to construct goals. The alternative is to focus your resolution on the input. Instead of resolving to lose weight, try an actionable resolution: “I’ll stop having dessert for lunch,” “No more pastry with my morning coffee” or “I’ll walk every day for 20 minutes.” Creating a goal that focuses on a well-specified input will likely be more effective than concentrating on the outcome: losing weight.

Focusing on input is better for several reasons. Think about Alex’s resolution of losing a pound a week. If you’ve ever tried this, you probably know the horrible feeling you get after you work hard on your goal all week, only to step on the scale and realize that instead of losing weight, you’ve actually gained a little. A few weeks like this and the diet is history — why suffer if it doesn’t help? The problem is that your weight depends on many things that are out of your control in the short term between weigh-ins. Each time you are disappointed by the outcome, you feel disproportionately bad. Behavioral economists Shlomo Benartzi and Richard Thaler have shown how losses loom larger than gains for those investing in the stock market. Consider a person in his 20s who invests money in the stock market for his retirement. Sometimes his portfolio goes up, sometimes down. In the long run his portfolio will do well, so he needs to learn to not focus on the painful losses in between.

The idea works for dieting as well. The negative feeling you get when you fail to meet your weekly weight-loss goal is much more powerful than the positive feeling you get when you meet your goal of losing a pound a week. By changing your goal to what you eat — something you can actually control — you can avoid the disappointment.

The idea of focusing on the input rather than the output is effective for more than just dieting. In our recent book, The Why Axis, John List and I discuss the emerging science behind incentives, including in education. To pick one example, economist Roland Fryer wanted to see what works best in motivating children to do better in school. In some cases, he gave students incentives based on input, like reading certain books, whereas in others, the incentives were based on output, like results on exams. His main finding was that incentives increased achievement when based on input but had no effect when based on output. Fryer’s conclusion was that the incentives for inputs might be more effective because students do not know how to do better on an exam, aside from general rules like “study harder.” Reading certain books, on the other hand, is a well-defined task over which they have much more control.

(MORE: Top 10 Commonly Broken New Year’s Resolutions)

Back to your resolution. You won’t always be successful, but as long as you have direct control over your goal, you have a much higher chance of success. And it’s easier to start again if you fail, because you know exactly what you need to do.

The idea of focusing on the input rather than the output is not unique to dieting. Say that you want to cut down on your spending. A good goal would be “I’ll make my morning coffee at home instead of going to Starbucks,” or “I’ll bring healthy lunch from home instead of the expensive and not so good food I buy at work.” These are well-specified action-based goals for which you can measure your success easily. “I want to spend less money” isn’t, because it’s too general. Similarly, if you want to spend more time with your family, don’t stop with this general wish. Think about an actionable habit that you could adopt and stick to, like a family movie night every Wednesday.

In the long run, these new goals could become a habit and, as such, can stick. Losing weight is not a habit; skipping the morning pastry is. What’s really nice about this goal is that as long as you don’t overcompensate by eating two desserts for lunch, you’ll also eventually meet the desired output.

Gneezy is the Epstein/Atkinson endowed chair in behavioral economics and professor of economics and strategy at the Rady School of Management at the University of California, San Diego. He is the co-author, with List, of The Why Axis: Hidden Motives and the Undiscovered Economics of Everyday Life.


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