Summer is fast approaching; a season often associated with rising anxieties about wearing bathing suits in public and renewed commitments to lapsed New Years’ resolutions or $150/month gym memberships.  According to the latest numbers, the average American is carrying around an extra 20 pounds, and about one third of Americans would have to lose 40 pounds or more to achieve a healthy weight.  Just how close will those weekly spinning classes get you toward your weight-loss goal?  Likely, not very close.

Research has shown that physical activity is not a very effective strategy for losing weight.  It can be very helpful as an adjunct to other efforts, and it is important for health.  However, it is not likely to result in substantial weight loss for several reasons.  First, for most people trying to lose weight, they need to burn at least 500 calories more than they take in every day to lose about 1 pound per week.  (Note: this is simplistic estimate – you can explore the calculator at to determine your own calorie requirements.) In order to achieve this caloric deficit through exercise alone, one could: run for 1 hour, bike for 2 hours, or walk for 2.5 hours . . . every day!  In fact, those estimates represent a bare minimum considering that most people currently consume more calories than they burn every day.  So the “calorie deficit” one would need to achieve without changing dietary intake could be more like 700-1000 calories per day below current consumption patterns; meaning one would have to double those exercise commitments. Who has that kind of time?

Second, studies have shown that people typically compensate for exercise by eating more.  In other words, people “un-do” at least some of the work they did to burn the calories by overeating later.  Moreover, some research shows that even thinking about exercise can lead us to eat more.  The simple act of imagining performing some strenuous activity can lead us to underestimate the calories in the food we eat (to a greater degree than we normally do) and reward ourselves by eating more.

Third, even if the average person could find the time for a daily 6-10 mile run, it would be difficult to maintain this pattern for very long.  For a 40 year old, 5’5”, 163 pound woman wanting to lose 20 pounds, it would take 6 months of daily 3-hour walks to reach her weight loss goal without changing her diet (assuming she consumes an average 2200 calories per day).  Without exception, sustained weight loss requires serious time, effort, and commitment.  It can take1-3 years to “re-set” your body (and mind) at a lower weight, and maintaining this weight loss is typically a lifelong commitment.  When you think about changes you can realistically make, they need to be changes you can stick with for years, and preferably for life. The main reason that weight-loss efforts of any kind fail is that people cannot maintain them for the long haul.

Obesity 101 book cover

Unfortunately, there are no quick fixes.  Losing weight and keeping it off requires time, effort, and patience; but it can be done.  Importantly, small but sustainable changes can add up to a significant impact over time. It may be difficult to find the motivation to enact these kinds of changes when the goal of unveiling your new beach body in summer 2013 is so far away.  However, it is better than the alternative of suffering through the latest weight loss fad (feeding tubes anyone?) over and over again every spring.


For a more comprehensive review of weight loss tools and programs, as well as many other topics, check out our book Obesity 101.