We treat height/weight tables as if they are truth. We believe they are based on sound science. But, in fact, most height/weight tables are based on questionable research which began in the early 1900s when the Metropolitan Life Insurance Company decided to find a way to make more money. The plan was to charge higher premiums, or refuse to insure applicants with certain risk factors. They decided the risk factor would be weight, partly because it is easy and cost effective to measure. They did some flimsy research, which resulted in height/weight tables that have been the foundation for weight recommendations for decades. Few people in the U.S. have escaped having their own weight compared to them.
The problems with their research are many, and started when they selected their subjects. They only studied their life insurance policy holders, who:
- Are not representative of Americans.
- Weigh five to ten pounds less than the average American.
- Have mortality rates up to 40% lower than the general population.
And there are even more methodological flaws in the studies:
- Mortality was defined as the cashing in of a policy, not the death of a person. (In other words, one person could hold 5 policies, when they were cashed in, it was recorded as 5 deaths.)
- All persons were included in the 1959 study whether the policy was purchased in 1935 or in 1953...what sounds like a 20-year study has an average follow-up of 7.8 years.
- The policyholders were never questioned about eating or exercise habits (which impact mortality regardless of weight).
- Weights and heights were self-reported in 10 to 20 percent of cases.
- Weights were recorded only once, so we don't know if policyholders lost or gained any weight during the study--which they probably did (one study in the 80s found that ½ of adult Americans gained or lost up to 15% of their body weight over 10 years!).
Okay, these innumerable flaws are interesting. But it gets even worse. Bear with me here.
The first weight table was actually based on the average weights of policyholders sampled. So, the average weight of a 5'4" woman who was 20 to 29 years old was 126 pounds. For a woman who was 60 to 69, the average weight was 144 pounds. For some unknown reason, they picked this average weight as the weight recommend for everyone. Then they decided overweight was anything over this average weight. However, studies showed that mortality did not increase appreciably until a person was at least 20 percent over average weight (which was 151 pounds for the 20‑29 year old woman, and 172 pounds for the 60-69 year old woman).
So, the insurance company decided that anyone who was 20 to 30% above average weight would have to pay higher premiums. So a woman 20-29 years old who weighed over 151 pounds would have to pay more.
But these weight tables have changed, and not necessarily in response to sound science. In fact, recommended weights follow societal trends.
The following chart shows how the Metropolitan Life Height/Weight Tables have changed, specifically for a 5'4" woman:
And now the worst part: when the weight recommendations were LOWERED, they were lowered more for women than for men. When weight recommendations INCREASED, they increased more for men than for women. The result was that men could be larger and still be considered healthy, while women needed to be smaller and smaller to be considered healthy. This is the OPPOSITE of research conclusions, which show that women typically can carry more weight than men and still be healthy. What do you think of that?
But the life insurance industry's conclusions have not only been accepted as truth, most people interpret them to mean that any degree of overweight will increase mortality. Glenn Gaesser, author of Big Fat Lies, exposes how there has been little critical evaluation of the data, and as a result, the belief that weight is a primary determinant of health problems has been influencing scientific investigations ever since. While some types of obesity present health risks for some individuals, the level of fatness that poses health risks cannot be determined from a height/weight table or percent of body fat testing.
One day we will realize that for most Americans, and indeed most people in this world, weight need not be an issue in regards to health.