Keith Burgess-Jackson, J.D., Ph.D.

Blame the Doritos! Unbelievable. Why is it so hard for people to understand that body weight is a function of three things: (1) metabolism, (2) caloric intake, and (3) caloric expenditure? There's little a person can do about his or her metabolism, which slows with age. The two things that can be controlled are caloric intake and caloric expenditure. If you take in more than you expend (via exercise), you gain weight. It's a law of nature, folks! You can't fight it! To lose weight, you must take in fewer calories than you expend. To stay at the same weight, you must take in exactly what you expend: no more and no less. Is there a connection between people's inability to live within their budgets and their inability to regulate their diets? Perhaps there has been a decrease in self-control during the past few decades, but why would that be? Oh, wait; it's the Doritos!