The Real Reason You Can't Lose Those Last Five Pounds

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If you can't seem to shave off those last ten pounds in your weight loss goal, marketing researchers might have an idea why: You could be overestimating your progress and underestimating the weight of your bad behavior. That is, you're unconsciously making little progress where you think you've made big strides. According to a new study, it's a pretty common thought process for those trying to lose weight or save money. "When people aren't keeping track of how they're doing with their goals, they tend to think that the good behaviors have a larger impact than the bad behaviors," says co-author Caleb Warren, a marketing professor at Texas A&M. 

Think about a person with a goal to lose ten pounds, Warren says. If that person ate healthy one day and lost one pound, they would see that as a big step and confirmation of their progress, both now and in the future. But if they didn't exercise the following day and gained one pound, they might not see the behavior as making a huge impact and see it as a one-time occurrence, or an exception. "When you're moving towards a goal, one step forward seems much larger than one step backwards," says Warren. And the problem is, these exceptions add up.

The error is known in psychology as a "confirmation bias" — the idea that when a piece of information fits in with your preconceived expectations, you tend to readily accept it without much thought. Along with co-author Margaret Campbell, he conducted seven studies at the University of Colorado Boulder comparing student's perceived progress with their actual results in situations like eating carrots versus skipping on a donut, or saving $45 versus spending it. In all the experiments, the students believed their goal-consistent behaviors (like refusing the donut) helped their progress more than the bad behaviors (like not eating carrots) actually hurt it. If you're refusing a donut and not eating a carrot, progress isn't really being made — it's just your perception.


But being mindful of this potential thought glitch can reduce what Caleb and Campbell call "progress bias." And the best way to do this could be recording your data in a tangible form. "Being more aware of your actual progress and using some of the tools that are becoming increasingly available to track progress will help," Warren says. "There are now more devices than ever to help consumers monitor their goal progress more closely." These include step counters or health apps that record how many calories you've consumed, how much you've burned, and other useful info. Without something like a FitBit — which provides an explicit look at your data — it's really easy for you to assume you're progressing and for the bias to kick in, says Warren. A 2013 study published in JAMA found that overweight people who used mobile apps to track their daily progress lost more weight (about 6 pounds more) at a constant rate than those who didn't — and the app users also stayed more committed.

Having solid objectives will also help. "If there's a clear goal to lose 10 pounds then you can take a look to see if you've made the progress to get there, or not," says Warren. "But if the goal is just to lose some weight it's really easy to think that you've made it there even if nothing much has changed."