Take coronary artery disease (atherosclerosis), for example—the number one killer in the developing countries. Conventional wisdom tells us that obesity itself is a major cause of clogged arteries—the rationale being that more fat on the body equals more fat in the blood stream equals more fat build-up in the arteries. However, most of the studies that have looked at the relationship between body weight (or body fat) and atherosclerosis—via coronary angiography or by direct examination of artery disease at autopsy—find that fat people are no more likely to have clogged arteries than thin people.
In some instances results entirely opposite to conventional wisdom are observed. For example, in U.S. when researchers at the University of Tennessee evaluated coronary angiograms of more than 4,500 men and women, they found that the risk of having a clogged artery actually decreased as body weight increased. In other words, it was the fat men and women who had the cleanest arteries. Although this finding is exceptional, the preponderance of angiography studies of this nature do undermine the notion that obesity inevitably results in clogged arteries.
Furthermore, the findings from angiography studies are consistent with countless autopsy studies—dating back to the middle of this century—of the link between body weight (or body fat) and arterial disease. The large-scale International Atherosclerosis Project, for example, conducted in the late 1950s and early 1960s, concluded after analyzing 23,000 sets of coronary arteries—obtained at autopsy—that no measure of body weight or body fat was related to the degree of coronary vessel disease. The obesity-heart disease link is just not well supported by the scientific and medical literature.
Thinner not Necessarily Healthier
The same could be said for the notion that thin people are healthiest and can expect to live longer than everybody else. Contrary to the prevailing medical mindset, the "thin-livelongest" studies frequently cited by the more vocal of the anti-fat crusaders are far outnumbered by studies demonstrating that body weight—aside from the extremes—is not really all that strong a predictor of death rates, or overall health for that matter.
A 1996 publication by researchers at the National Centre for Health Statistics and Cornell University illustrates perfectly. After analyzing the results from dozens of published reports on the impact of body weight on death rates, encompassing
more than 350,000 men and nearly 250,000 women, the researchers found that moderate obesity (no more than about 22.7 kg. in excess of the so-called ideal body weight) increased the risk of premature death only slightly in men, and not at all in women, during follow-up periods lasting up to 30 years. In fact, the researchers found that thin men even within the range recommended by the current U.S. government guidelines had a risk of premature death equal to that of men who were extremely overweight. The researchers warned in their summary comments that "attention to the health risks of underweight is needed, and body weight recommendations for optimum longevity need to be considered in light of these risks."
In America the Metropolitan Life Insurance Company introduced its tables of "ideal" weights in 1942 the company called them "desirable" weights in 1959, and did away altogether with the terms "ideal" and "desirable" in 1983 we have been operating under the weight loss industry-reinforced assumption that weighing more than what the height/weight charts say we should weigh is a sure sign of poor health and greatly increases risk of premature death. However, the majority of body weight-mortality investigations have shown that weighing 90 pounds, or 30 pounds, or even 50 pounds in excess of the height-weight chart recommendations is associated with little, if any, increased risk of an early check-out.
For example, the current U.S. government guidelines indicate that a 5'4" woman should weigh between 111 pounds and 146 pounds, and a 5'10" man should weigh between 132 pounds and 174 pounds. According to the 1996 study previously mentioned, a 5'4" woman and 5110" man could weigh close to 200 pounds before their risk of premature death goes up appreciably (excess body weight seems to be riskier in men than in women). This suggests that there are a great many "overweight" Americans especially women who are agonizing unnecessarily about those numbers on the bathroom scale.
So if being a little fatter than average might not be so bad, and being thin (at least for men) might not be so good, what does this say about body weight and health? If the concept of an ideal weight is little more than statistical fiction, should we just chuck the bathroom scale, kick back on the sofa with a bag of chips in one hand and the remote control in the other, and nestle into total couch-potato-hood of course not (although chucking the bathroom scale is probably a good idea). It's just that body weight, and even body fat for that matter, do not tell us nearly as much about our health as lifestyle factors, such as exercise and the foods we eat. Consider the following scenario.
Randomly select a few hundred men and women (matched for age and smoking habits) and divide them into two groups based on body fat: lean and fat. Next take each person's blood pressure, draw some blood and determine each person's serum lipid levels, and have each person perform a glucose tolerance test (to get an idea of each person's insulin sensitivity). You will find, on average, higher blood pressures, unhealthier blood lipid profiles, and poorer glucose tolerance/insulin sensitivity in the group of fat men and women.
Does this mean that the higher body fat levels caused the health problems? No. It just means that you are more likely to find these kinds of metabolic disorders in fat men and women. But associations do not prove cause-effect. Just because you are more likely to observe high blood pressure, elevated blood lipids and glucose intolerance in fat persons does not prove that body fat is the cause of these health problems, nor does it mean that a fat person has to become lean in order to resolve these health problems. The proof of this assertion is quite straightforward. Get these fat men and
women to start an exercise programmed and eat healthier foods and see how they do. Numerous research studies have done just that. A few examples are described below.
