The recent AARP study of over 500,000 people on obesity and mortality failed to analyze important data, which could significantly alter their conclusions… that being a few pounds overweight could be fatal.

The study, titled “Overweight, Obesity, and Mortality in a Large Prospective Cohort of Persons 50 to 71 Years Old”, (The New England Journal of Medicine (August, 2006, (Vol 355, No.8) stated that “Excess body weight during midlife, including overweight, is associated with an increased risk of death,” The authors also wrote “…weight loss after the age of 50 years was more strongly associated with the risk of death than was weight gain (data not shown).”

According to Dr. Abby Aronowitz, Director of, the second point is buried within the text, rather than highlighted in the conclusion.

Additionally, the authors wrote that, “Because we cannot rule out the possibility that unmeasured or unknown confounding factors accounted for the associations observed in our study, we cannot conclude with complete certainty that the relation between adiposity and the risk of death is causal.”
But this pivotal point was also obscured, along with a failure to utilize data that might otherwise have shed light on this concept.

Although the researchers collected information on physical activity, they provided no analysis – even though a significant body of credible evidence has found good health to be associated with fitness levels. Comparisons between “overweight’ active people and “overweight” inactive people would likely have yielded a completely different headline.

Similarly, although yo-yo dieting has been associated with coronary heart disease, diabetes and hypertension – and may in fact represent the true risk factor between excess weight and these conditions – the study made no assessments involving weight cycling.

But even when statistical data was reported without bias, the manner in which the authors chose to frame their conclusions is up for debate.

Consider the following statement, “Excess weight accounted for approximately 7.7 percent of all premature deaths among men and 11.7 percent of all premature deaths among women in the overall cohort.”

Would the cultural impact of this information be different if it was reported that 92.3% percent of all premature deaths among men and 88.3% of all premature deaths among women were due to factors other than weight? The fact that they cannot conclusively determine whether these small percentages were actually due to excess weight weakens the study’s conclusions even further.

Likewise, while there is great attention paid to how smoking affects weight and mortality, one stunning piece of statistical information present in the study failed to be noted. Using their published data, Dr. Aronowitz added up the number of deaths from current smokers in the three lowest BMI categories, (a total of 2,252), along with the number of deaths from smoking in the three highest BMI categories (1,595). One cannot help but note there were approximately 70 percent more deaths in leaner smokers than heavier smokers. This suggests that having a higher BMI may have a protective effect against cancer - a finding that has been suggested by other studies. Yet this too goes completely unreported in the conclusion.

The CDC National Center for Health Statistics report that although Americans weigh more than they did in the past, U.S. life expectancy is at an all-time high.

Unfortunately, studies like this one not only contradict that logic, but also add anxiety and unproven fears to the emotional load already being carried by those struggling to lose weight.

Author's Bio: 

Dr. Abby Aronowitz is a frequently cited Expert for, a writer for AOL Diet and Fitness, and a weekly columnist for (in the Worst Foods newsletter). Formerly a consultant to Weight Watchers International, Inc., she spent 16 years as a private practice psychologist, and authored "Your Final Diet." ("This is fabulous!" Senator Hillary R. Clinton). She has spoken for the National Organization for Women (NOW) and Mensa, and graduated from Columbia University. Learn more about her work at