How to Get to Your Healthy Weight
04 December 2008
What's a Healthy Weight?
Although nutrition experts still debate the precise limits of what constitutes a healthy weight, there's a good working definition based on the ratio of weight to height. This ratio, called the body mass index (or BMI for short), takes into account the fact that taller people have more tissue than shorter people, and so tend to weigh more.
Dozens of studies that have included more than a million adults have shown that a body mass index above 25 increases the chances of dying early, mainly from heart disease or cancer, and that a body mass index above 30 dramatically increases the chances. Based on this consistent evidence, a healthy weight is one that equates with a body mass index less than 25. By convention, overweight is defined as a body mass index of 25 to 29.9, and obesity is defined as a body mass index of 30 or higher.
Nothing magical happens when you cross from 24.9 to 25 or from 29.9 to 30. These are just convenient reference points. Instead, the chances of developing a weight-related health problems increases across the range of weights.
Muscle and bone are more dense than fat, so an athlete or muscular person may have a high body mass index, but not be fat. It's this very thing that makes weight gain during adulthood such an important determinant of weight-related health—few adults add muscle and bone after their early twenties, so nearly all that added weight is fat.
Nothing magical happens when you cross from 24.9 to 25 or from 29.9 to 30. These are just convenient reference points. Instead, the chances of developing a weight-related health problems increases across the range of weights.
Muscle and bone are more dense than fat, so an athlete or muscular person may have a high body mass index, but not be fat. It's this very thing that makes weight gain during adulthood such an important determinant of weight-related health—few adults add muscle and bone after their early twenties, so nearly all that added weight is fat.
Calculate your BMI
Here's how to determine your body mass index: Divide your weight in pounds by your height in inches. Divide the answer by your height in inches. Multiply the answer by 703. For an easier way, the National Heart, Lung and Blood Institute offers an online BMI calculator or simple BMI tables.
Waist Size Matters, Too
Some research suggests that not all fat is created equal. Fat that accumulates around the waist and chest (what's called abdominal adiposity) may be more dangerous for long-term health than fat that accumulates around the hips and thighs.Some studies suggest that abdominal fat plays a role in the development of insulin resistance and inflammation, an overactivity of the immune system that has been implicated in heart disease, diabetes, and even some cancers. It's also possible, of course, that abdominal fat isn't worse than fat around the hips or thighs, but instead is a signal of overall body-fat accumulation that weight alone just doesn't capture.
In people who are not overweight, waist size may be an even more telling warning sign of increased health risks than BMI. The Nurses' Health Study, for example, looked at the relationship between waist size and death from heart disease, cancer, or any cause in middle-aged women. At the start of the study, all 44,000 study volunteers were healthy, and all of them measured their waist size and hip size. After 16 years, women who had reported the highest waist sizes—35 inches or higher—had nearly double the risk of dying from heart disease, compared to women who had reported the lowest waist sizes (less than 28 inches). Women in the group with the largest waists had a similarly high risk of death from cancer or any cause, compared with women with the smallest waists. The risks increased steadily with every added inch around the waist. And even women at a "normal weight"—BMI less than 25—were at a higher risk, if they were carrying more of that weight around their waist: Normal-weight women with a waist of 35 inches or higher had three times the risk of death from heart disease, compared to normal-weight women whose waists were smaller than 35 inches. The Shanghai Women's Health study found a similar relationship between abdominal fatness and risk of death from any cause in normal-weight women.
Some research suggests that not all fat is created equal. Fat that accumulates around the waist and chest (what's called abdominal adiposity) may be more dangerous for long-term health than fat that accumulates around the hips and thighs.Some studies suggest that abdominal fat plays a role in the development of insulin resistance and inflammation, an overactivity of the immune system that has been implicated in heart disease, diabetes, and even some cancers. It's also possible, of course, that abdominal fat isn't worse than fat around the hips or thighs, but instead is a signal of overall body-fat accumulation that weight alone just doesn't capture.
In people who are not overweight, waist size may be an even more telling warning sign of increased health risks than BMI. The Nurses' Health Study, for example, looked at the relationship between waist size and death from heart disease, cancer, or any cause in middle-aged women. At the start of the study, all 44,000 study volunteers were healthy, and all of them measured their waist size and hip size. After 16 years, women who had reported the highest waist sizes—35 inches or higher—had nearly double the risk of dying from heart disease, compared to women who had reported the lowest waist sizes (less than 28 inches). Women in the group with the largest waists had a similarly high risk of death from cancer or any cause, compared with women with the smallest waists. The risks increased steadily with every added inch around the waist. And even women at a "normal weight"—BMI less than 25—were at a higher risk, if they were carrying more of that weight around their waist: Normal-weight women with a waist of 35 inches or higher had three times the risk of death from heart disease, compared to normal-weight women whose waists were smaller than 35 inches. The Shanghai Women's Health study found a similar relationship between abdominal fatness and risk of death from any cause in normal-weight women.
Measuring your waist is easy, if you know exactly where your waist really is.
Wrap a flexible measuring tape around your midsection where the sides of your waist are the narrowest. This is usually even with your navel. Make sure you keep the tape parallel to the floor.
An expert panel convened by the National Institutes of Health concluded that a waist larger than 40 inches for men and 35 inches for women increases the chances of developing heart disease, cancer, or other chronic diseases. Although these are a bit generous, they are useful benchmarks.
Waist size is a simple, useful measurement because abdominal muscle can be replaced by fat with age, even though weight may remain the same. So increasing waist size can serve as a warning that you ought to take a look at how much you are eating and exercising.
An expert panel convened by the National Institutes of Health concluded that a waist larger than 40 inches for men and 35 inches for women increases the chances of developing heart disease, cancer, or other chronic diseases. Although these are a bit generous, they are useful benchmarks.
Waist size is a simple, useful measurement because abdominal muscle can be replaced by fat with age, even though weight may remain the same. So increasing waist size can serve as a warning that you ought to take a look at how much you are eating and exercising.
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