The tempting marketplace.

Obesity researchers are using mapmakers to graphically demonstrate that kids walk home from school past lots of places that sell the kind of food that makes them fat. Wouldn't it be better if there were only fruit stands?

Michele and Gene Burgese, who own Red's Hoagies across from Southwark, said they are happy to stock more fruit but doubt it will sell.

"Kids are kids," Michele Burgese said. "I don't think we ever sold an apple or banana to a kid," her husband said.

The only hope is to only sell fruit. Damn that free choice! People buy what they want. But if you smell fried chicken and doughnuts when you're walking down the street and hungry, you're going to want something lusciously fatty. I know what a fruit stand smells like. It doesn't make you feel like eating fruit. It makes you think I really should eat more fruit.

The hungry body feels powerfully drawn to foods that will pack on weight. This is the result of evolution in a world of scarce food, where people survived because strong instincts enabled them to zero in on the foods that would keep them going. We're not going to dawdle around this berry bush. We need to get something with fat and full of nourishment. Human organisms with an intense love of fruit died out in prehistoric famines.

The urge to eat fat is entirely healthy and normal. What is abnormal is that food is available everywhere. This is also a wonderful thing. Now, we're left to overcome our own healthy instincts because they've got a bad effect in our new, comfortable environment.

How can we possibly do that? Well, why are we not just saints in all aspects of our lives?

UPDATE: In the comments, there's a lot of discussion about whether it's better -- in fatness/slimness terms -- to live in the city or the suburbs.