Weight charts and tables and numbers and stats are so plentiful that you may think they’re totally reliable in predicting who’s healthy and who’s not. So here’s a surprise: They aren’t.
The problem is that real people and their differences keep sneaking into the equation. For example, the value of the Body Mass Index in predicting your risk of illness or death appears to be tied to your age. If you’re in your 30s, a lower BMI is clearly linked to better health.
If you’re in your 70s or older, no convincing evidence points to how much you weigh playing a significant role in determining how healthy you are or how much longer you’ll live. In between, from age 30 to age 74, the relationship between your BMI and your health is, well, in-between — more important early on, less important later in life.
In other words, the simple evidence of your own eyes is true. Although Americans sometimes seem totally obsessed with the need to lose weight, the fact is that many larger people, even people who are clearly obese, do live long, happy, and healthy lives. To figure out why, many nutrition scientists now are focusing not only on weight or weight/height (the BMI) but on the importance of confounding variables, which is sciencespeak for “something else is going on here.”
Here are three potential confounding variables in the obesity/health equation:
Adding to the confusion is the fact that an obsessive attempt to lose weight may itself be hazardous to your health. Every year, Americans spend $30 billion to $50 billion (yes, you read that right) on diet clubs, special foods, and over-the-counter remedies aimed at weight loss. Often the diets, the pills, and the foods don’t work, which can leave dieters feeling worse than they did before they started.
The chance that the diet fails is only half the bad news. Here’s the rest: Some foods that effectively lower calorie intake and some drugs that effectively reduce appetite have potentially serious side effects. For example, some fat substitutes prevent your body from absorbing important nutrients, and some prescription diet drugs, such as the combination once known as Phen-Fen, are linked to serious, even fatal, diseases.
The problem is that real people and their differences keep sneaking into the equation. For example, the value of the Body Mass Index in predicting your risk of illness or death appears to be tied to your age. If you’re in your 30s, a lower BMI is clearly linked to better health.
If you’re in your 70s or older, no convincing evidence points to how much you weigh playing a significant role in determining how healthy you are or how much longer you’ll live. In between, from age 30 to age 74, the relationship between your BMI and your health is, well, in-between — more important early on, less important later in life.
In other words, the simple evidence of your own eyes is true. Although Americans sometimes seem totally obsessed with the need to lose weight, the fact is that many larger people, even people who are clearly obese, do live long, happy, and healthy lives. To figure out why, many nutrition scientists now are focusing not only on weight or weight/height (the BMI) but on the importance of confounding variables, which is sciencespeak for “something else is going on here.”
Here are three potential confounding variables in the obesity/health equation:
- Maybe people who are overweight are more prone to illness because they exercise less, in which case stepping up the workouts may reduce the perceived risk of being overweight.
- People who are overweight may be more likely to be sick because they eat lots of foods containing high-calorie ingredients, such as saturated fat, that can trigger adverse health effects; in this case, the remedy may simply be a change in diet.
- Maybe people who are overweight have a genetic predisposition to a serious disease. If that’s true, you’d have to ask whether losing 20 pounds really reduces their risk of disease to the level of a person who is naturally 20 pounds lighter. Perhaps not: In a few studies, people who successfully lost weight actually had a higher rate of death.
Adding to the confusion is the fact that an obsessive attempt to lose weight may itself be hazardous to your health. Every year, Americans spend $30 billion to $50 billion (yes, you read that right) on diet clubs, special foods, and over-the-counter remedies aimed at weight loss. Often the diets, the pills, and the foods don’t work, which can leave dieters feeling worse than they did before they started.
The chance that the diet fails is only half the bad news. Here’s the rest: Some foods that effectively lower calorie intake and some drugs that effectively reduce appetite have potentially serious side effects. For example, some fat substitutes prevent your body from absorbing important nutrients, and some prescription diet drugs, such as the combination once known as Phen-Fen, are linked to serious, even fatal, diseases.
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