When it comes to weight loss, most of us would like to engage in what psychologists call "magical thinking." We'd like to believe that some easy trick or ritual would allow us to shed pounds while eating anything we liked. Wouldn't it be nice if consuming all our food before 6 p.m., doing yoga, or hopping on one foot for five minutes would allow us to chow down with all our favorite goodies and still lose weight?
Unfortunately, despite what legions of people with a book or a product to sell might claim, it's just not so. Yet it really is possible to come up with a system for losing weight. The real secret is this: It's all about calories.
Most of us have heard that sensible weight loss involves some combination of diet and exercise. As a physician, I'm surely not going to tell people to avoid exercise. For most people, exercise is a very healthy thing to do. But when it comes to losing weight, unless we're training for Olympics, effect of exercise is minor. What matters most is how many calories go down hatch.
This bears explaining. Our bodies use calories we consume to fuel our basic life- processes. The heart needs lots of fuel (calories) to beat its usual 100,000 times in 24 hours. The brain, liver and kidneys also require lots of fuel to perform their many chemical reactions and metabolic tasks. Most of calories we burn in 24 hours (about 1500 for women and 1800 for men) we would still burn even if we were in a coma.
It's true that working muscles in our arms, legs and trunk requires fuel (calories) as well, but you'd be amazed how long you would have to row, jog, swim or walk to burn calories in one slice of cherry pie. (Answer: In order to burn off 486 calories in a slice of cherry pie a 175-pound person would need to row for 35 minutes, jog for 37 minutes, swim for 41 minutes or walk briskly for 63 minutes.) For most of us it would be more practical to just not eat pie.
Each of us has a calories-per-day figure for maintaining body weight. If, on average, we eat that many calories, then we will maintain body weight, neither gaining nor losing. If we consistently eat more calories than our break-even number, then we will gain weight. The unused calories have to be stored somewhere, and will probably go into our body's fat cells. If we consistently eat fewer than our break-even number of calories, then we will lose weight. The body will get its fuel somewhere, and will burn off calories that have been put into storage in fat cells.
This is how it is. We just can't get around basic biology and physics.
So, if we're trying to lose weight, how do we choose what we do or don't eat? Well, sometimes, our choices are haphazard. A useful analogy concerns shopping. How in world could we do a good job of shopping without knowing prices of items we're putting in our shopping carts? Without knowledge of prices our choices in merchandise could easily exceed our budgets.