Don’t sweat the love handles and more!
From a new study in JAMA of 270,000 deaths:
Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
This meta-analysis confirmed what has been known and shown in the evidential data for well over half a century. Weight or BMI is simply not a measure that can be credibly used to predict mortality or health. This paper found no tenable difference in hazard ratios for mortality among BMIs of 18.5 through 35 — accounting for the overwhelming majority of the population. This study shared the same problems related to all meta-analyses which compile data from a vast array of souces, methodologies, etc… so caution is advised when interpreting the statistics. Since, the authors only consistently adjusted for age among those 65 years and older, this is the only figure that we can really compare, since age is the biggest risk for death. They lumped all the BMI categories over 35 together, which likely exaggerated the hazard ratios associated with most people in the obese category. Even so, among all of the most “obese” (BMIs 35+), they still could only find a mathematical 12% higher hazard ratio for mortality — a percentage than is not considered by any legitimate scientific organization to be tenable — in other words, no greater than might be due to random change, statistical or modeling error or a multitude of confounding factors.
More to the point, the crisis of obesity continues to be a manufactured crisis used by special interests who profit financially and politically from mandating diets, “healthy” foods, exercise programs, community designs, etc.
As is well documented, being underweight is associated with a much higher risk for mortality than even the most “morbidly obese” but there are no calls to address the excruciating stick (underweight) figures increasingly represented in media and pop culture and giving a very unhealthy message to young people and adults.
Here’s a better plan: do away with BMI. It is only relevant for the very high (40+), and the very low.
But the morbidly obese and anorexic are easily spotted. We don’t need no stinkin’ number.
BMI is nearly worthless. Even if it were corrected for the height error (every professional basketball player is obese?) and also accounted for age, it is still too simplistic. There are too many other factors that must be taken into account. We all have computers now (and routinely carry around at least one), we can handle something a little more computationally complex.
The data clearly show that health declines at extremely low BMI and at extremely high BMI (morbidly obese). It is clear that you are correct, BMI categories are inaccurately centered. The normal BMI category should be wider and should include at least the next higher category.
BMI classified ripped, hardened athletes as “obese”.
Quite simply, the current BMI categories are wrong. Until 1999 (I think) the categories were 22.5-27.5 normal, 27.5-32.5 overweight etc. If these mortality figures were re-evaluated with the original BMI categories, it might show this up. However, I think even these (older) categories should be re-evaluated as people are taller than they used to be (figures from the UK show increased height even during this century) and the BMI classifications do not relate as people get taller – ever seen a 6-foot person with a BMI of 25? They are either malnourished or have serious bone density issues.
BMI might be a very simple measurement, but its relevance to health is questionable (except at the extremes) and the classifications have been set with no reference to health outcomes. Obesity has become a political tool not a medical issue.
Sandy Szwarc at junkfoodscience.blogspot.org is a real expert on weight and health and has reported many times over years on studies showing that some overweight is associated with better health. She is terrific and I hope that she restarts her blog soon.