So what does that mean for the rest of us?
Cahn joined us for a question-and-answer session about that New Year's resolution you just made, and what you can do to beat the odds.
When people make a New Year's resolution to lose weight, how often do they succeed?
The data are not encouraging. There's some data you can look at in terms of gym memberships and gym attendance. It's a precipitous dropoff after the second week of February.
Are you saying that working out has to be part of any successful weight-loss program?
When people make a New Year's resolution to lose weight, there are better ways of approaching it. That' s a suboptimal resolution because we don't have direct control over our weight. There's a lot of factors that go into it: genetics, your environment, the medications you're on, what health conditions you have. We don't have 100 percent control over our weight. No one makes a resolution to lower their blood pressure just by sheer will alone.
So what's a better strategy?
The best way to make a resolution is to make it something that's under your control. Then it's your own behavior. You make a behavioral goal that is specific and measurable — and along with specific, objective and realistic.
Give me an example.
I'm going to get 20 minutes of physical activity twice a week for the first month of January, and then reassess. That's specific and it's measurable. There's a downside of having goals that are too ambitious, because it's discouraging when we fail. We feel bad about ourselves and we're more likely to give up. Smaller goals are better.
So you wouldn't recommend that someone set a goal of a specific number of pounds?
Some people are never going to be happy with their weight. Some people are always going to weigh more than they want to weigh. They don't have control. Why not focus on lifestyle factors that are reasonable and achievable for you? What's the healthiest lifestyle that you could adopt long-term and be happy?
If you or I go on a diet that makes us miserable, at some point you're going to get sick of having three green monster smoothies a day. If you had to wake up at 5:30 in the morning every day to go to the gym, indefinitely, you might lose body fat, but you could ultimately become fatigued and cranky, or just bored.
So what's the answer?
Build in rewards. Set small, proximal goals. Don't say "I'm going to work out twice a week indefinitely." Set some proximal goals and then reward yourself. One reward that I like and recommend is allow yourself to buy music, like songs on iTunes, and then let yourself listen to them when you're working out at the gym, or walking.
Obviously you want to avoid food-related rewards for yourself. That's counterproductive.
If you can do it with some support, like a buddy or an online community, you're more likely to stick with it.
Read more Goal Getter for healthy eating, weight loss and more.