Want to know the odds that your next diet will succeed? Don't look inside your refrigerator. According to a new study, you're better off taking a trip around your neighborhood.

Your mission: search for every fast-food restaurant, convenience store, and grocery store within half a mile in any direction from your home. Count every McDonald's, 7-Eleven, and Trader Joe's. (This mission does not require stopping to sample the merchandise. If you are so tempted, do your reconnaissance on Google maps, where you can search for businesses near your address.)

Then calculate your "Retail Food Environment Index" (RFEI). Add up the number of fast food restaurants and convenience stores (F+C), and divide that sum by the number of grocery stores (G). If there are no grocery stores in your neighborhood, your index is the sum of F+C. 

This number, according to researchers at the University of Alberta, is a good predictor of whether or not you will end up overweight. The researchers calculated the RFEI for 2900 adults who lived in Edmonton, Canada. People were significantly less likely to be overweight if they lived in a neighborhood with a RFEI of less than 3.0, and most likely to be overweight if they lived in a neighborhood with a RFEI of 5.0 or higher.

The researchers called these high-RFEI neighborhoods "obesogenic." The message is clear: live in these toxic environments at your own risk.

This study is just the most recent of a series of studies showing that temptation in your neighborhood can sabotage your diet. For example, a study published in April found significantly higher student obesity rates at schools that had at least one fast-food restaurant within one-tenth of a mile from school grounds. Other studies across the U.S. have linked high RFEIs to higher rates of obesity-related diseases and deaths.

We all want to believe that our choices are self-determined and free from external influences-especially when the external influence is a Dunkin Donuts down the street. What does it matter if temptation abounds? I have the strength to say no! But the truth is that inner willpower is often overcome by the ease of giving in to temptation.

What makes these environments obesogenic is not just how they limit your choices, but how they sap your of your strength. Nobody has unlimited willpower. Every time you say "no" to the siren call of fries and a burger, your willpower is depleted a little bit. If you have to say "no" every hundred feet, that willpower gets exhausted. Eventually, when you are tired or just plain tired of saying no, you will give in. It's much easier to lose weight when you don't have to constantly make the decision to resist.

I'll admit, I'm susceptible to this effect. The RFEI of my current home is 4.32, compared to 3.85 for the neighborhood I moved from 3 years ago. Perhaps that (or more specifically, one particular restaurant across the street) explains the few pounds I've gained since I moved here.

What's the solution? Many researchers and policy-makers are advocating for laws that would limit fast-food restaurants, or provide funding to support high-quality groceries stores in neighborhoods that rely on corner convenience stores. This might be a good long-term strategy for the public good, but it won't save your diet in the meantime.

Here are some strategies (short of moving) that can help you handle a high-risk food environment:
1. Limit the circumference of your food environment. Commit to eating at home more often, where you have more control.
2. Plan your meals ahead of time. You don't want to be making the choice of where to grab dinner when you're hungry and exhausted, driving home past all those tempting restaurants.
3. Do a little homework and find out what the healthiest thing is on the menu of every local restaurant. Go on a scavenger hunt to the convenience stores, and scan the shelves for healthy options. Knowing in advance will help you make healthier choices when your stomach is growling.
4. If you live in a neighborhood full of of fattening options, the social norm is to eat there. Otherwise, the places would go out of business. Set your own social norm in your own social circle. Don't let a high-calorie dinner and dessert in the neighborhood restaurant become the default for catching up with friends. Find ways to socialize that don't involve going out for food or drinks.

New study reference: Relation between local food environments and obesity among adults. JC Spence, N Cutumisu, J Edwards, KD Raine, & K Smoyer-Tomic. BMC Public Health (in press).

You are reading

The Science of Willpower

What Moment Will Define You in 2014?

Try this alternative to a New Year's resolution to create your dream 2014.

How to Quit Almost Anything

Tap into your "I want" power to find your "I won't" power.

What the Stock Market Can Teach You About New Year's Resolve

A market quirk called the January Effect reveals the economics of resolutions.