Here’s the line of thinking: being overweight is tied to conditions like high blood pressure, high cholesterol and Type II diabetes, which, therefore, raises the risk of heart disease, stroke and some cancers. Falling into the obese category raises the risks even more. Therefore, conventional wisdom tells us that being overweight or obese means a higher morbidity rate and shorter lifespan.
The problem is a lot of the latest epidemiological studies and population statistics aren’t bearing this out. In fact, in general terms, people in the overweight category are outliving those in the underweight category and living just as long and healthy as those in the normal weight category.
How can this be? The categories (obese, overweight, normal, underweight) are determined by the Body Mass Index (BMI). BMI is derived from a formula using only weight and height. And, by the way, BMI is the number your doctor is using to tell you whether or not you need to lose weight. To say this is an imperfect way to determine someone’s health is an understatement. The following factors are far better indicators of health and longevity than BMI:
- Body Composition: It turns out Mom was right to point out that her daughter wasn’t fat, she was big boned. Lean mass such as muscle and bone weighs more than body fat. It’s far more important, in terms of measuring one’s health, that one has a favorable lean to fat mass ratio than to fall into the normal range on the BMI chart. Many of the fittest men and women on the planet (think premier athletes) fall into the overweight and obese ranges on the BMI chart because they have higher than average lean mass. Conversely, some of the most out of shape but genetically thin couch-potatoes fall into the normal category on the BMI.
- Body Fat Location: What is considered healthy body fat not only depends on how much we have but also where our bodies store it.
- Subcutaneous fat is the layer of fat that lies just beneath the skin and a certain amount of this fat is necessary for survival. Women have and need more than men. Genes determine where we store this fat. Some women store it predominantly in the hips and thighs (pear-shape), others carry it more in the arms, shoulders and chest (upside-down pear-shape) and still others (lucky ducks!) seem to carry it evenly between the upper and lower body (hour glass). The appearance of subcutaneous fat also differs from one person to another. Sometimes this layer is smooth, other times it’s dimpled (otherwise known as cellulite) and what kind you have is determined by genes and age. There is no difference in the health implications between smooth and dimpled subcutaneous fat. There’s no exercise a person can do or diet she can follow that will change dimpled fat to smooth. Ditto on shifting the storage of subcutaneous fat from one part of the body to another. If a woman falls into the normal range for body fat percentage (21-31%) and it’s predominantly subcutaneous fat, she’s considered healthy no matter where she falls on the BMI chart. The normal range for men is 14-24%. Furthermore, having more subcutaneous fat than we need may hurt our pride but it doesn’t appear to have significant health consequences.
- Visceral fat surrounds the organs of the abdomen. This is the dangerous body fat. If a person carries her fat predominantly in the abdomen (apple-shaped), she is at higher risk of life-shortening diseases, even if she falls into the underweight or normal categories on BMI. Regular exercise and proper diet can and does reduce the amount of visceral fat in an individual.
- Lifestyle: The studies continue to roll in and support the notion that the overweight and physically active are healthier and live longer than the normal weight and sedentary. In addition, the more time one spends sitting each day, the higher the risk for disease (heart disease in particular) even if one is at a normal weight, eats a healthy diet and exercises regularly.
The problem is, more often than not, the overweight and obese are advised to select a weight on the BMI chart that falls in the normal range for that individual’s height and to make reaching that weight the only path to health. Often this will require, after the reduction of visceral fat, losing a lot of subcutaneous fat. The body will resist doing this because it views that phenomenon as life-threatening. This is counterproductive and this latest study done on fourteen contestants from Season 8 of “The Biggest Loser” proves it.
Our society doesn’t help. We put the focus on body image as opposed to health. This compels us to chase unhealthy and unrealistic scale numbers and clothing sizes.
The facts are clear on what the goal should be and the proper path by which to achieve it: a healthy diet and regular cardiovascular, strength, flexibility and balance training will lead to increased lean mass. This will reduce a person’s visceral fat and put her lean to fat mass ratio in the healthy range. People who accomplish and maintain this are more likely to live longer, healthier lives than those who don’t. BMI is irrelevant.
This may mean you won’t ever see that ideal number on the scale or slip into that size 4 dress. And we – as individuals and as a society – need to learn to be okay with that if we truly care about health and happiness.