Of the foods we eat, fat is the richest source of energy, possessing nine calories in each gram. Protein and carbohydrates each have four calories per gram, while soluble fiber has about two calories per gram. For those among us who like a drink now and then, every gram of (undiluted) alcohol holds seven calories.
How does it all add up? While energy needs vary depending on age, body size and activity level, most of us require about 2,000 calories a day to go about our business.
Unlike cars, though, when we put extra fuel into our tanks, it just doesn't spill out onto the ground. Instead, our bodies convert that excess to fat. And it adds up quickly: Every 3,600 calories you pack away means another pound on your belly. Or elsewhere.
The key to keeping weight off is to limit the amount of calories you take in to the amount you burn off. Sounds easy enough, right? Just remind me of that next time I'm staring down a nice rib-eye at Red Prime. I might end up eating my words.
Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF's senior vice president and general counsel.