To Obese, Or Not To Obese

Ah, that is the question.  The London Times Online addresses the weighty issue in Obesity: does size matter?  Recently the CDC had to pull back from estimates of 400,000 excess deaths per year from obesity, to about 112,000 per year, according to CNN.

Last year, the CDC issued a study that attributed 400,000 deaths a year to mostly weight-related causes and said excess weight would soon overtake tobacco as the top U.S. killer. After scientists inside and outside the agency questioned the figure, the CDC admitted making a calculation error and lowered its estimate three months ago to 365,000.

The new study attributes 111,909 deaths to obesity, but then subtracts the benefits of being modestly overweight, and arrives at the 25,814 figure.

Well, I'm not buying what they're selling, at least not yet.  Benefit from being "modestly overweight?"  How do they suppose that benefit comes about?  This screams "methodological error" to me, and to others apparently.

Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women's Hospital in Boston, said she is not convinced the new estimate is right.

"I think it's likely there has been a weakening of the mortality effect due to improved treatments for obesity," she said. "But I think this magnitude is surprising and requires corroboration."

From an orthopaedic standpoint I will tell you that there is no doubt about increased morbidity from being overweight.  That increased morbidity shows up in my office all the time.  Foot pain, knee pain, back pain, neck and shoulder pain - all are more common in individuals who are overweight with poor fitness.

Your knee sees three times your body weight in force across the joint when you walk, and seven times BW when you run.  That means that for each pound you gain your knees think you gained 3 to 7 lbs.  These increased forces, along with the loss of flexibility and strength that usually accompanies the weight gain, lead to aching joints from a variety of causes, including arthritis.

In addition, if you are obese, with a BMI of greater than 30, you have 3 times the usual risk of complications when undergoing elective knee replacement surgery.  Problems such as blood clots, infection, increased blood loss and neurovascular injuries are all more common in the obese, and the result of the surgery less predictable.  These studies have been done, including one excellent one published just last September from Johns Hopkins.

There are lots of body weight calculators available on the net.  This one seems reasonable, and also gives a BMI calculation.  It takes into account the admittedly low weights listed in the older tables, like this one.

My recommendation?  Try for less than 125% of ideal body weight.  The Met Life tables have been criticized for listing too low a weight, so I'll accept that criticism.  Thus, if your IBW by the tables is 160 lb., your upper limit would be 200 lb.  There is therefore really no reason for anyone whose job doesn't involve pushing around defensive linemen on fall Sundays to weigh more than 300 lb.

The Times article finishes with some sage advice, for Brits and Yanks, after pointing out that both heart disease and Type II diabetes are associated with obesity.

We should rejoice that only 100,000, and not 400,000, Americans are dying principally from obesity each year. However, as a nation we have never been as plump as the Americans and this only comparatively happy finding shouldn’t lull us into a sense of unwarranted complacency.

We should follow the example of the London surgeon, and watch our waistline, take long walks and if necessary say no to calorie-dense foods.