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Weight loss won’t prevent diabetes

Posted by medconsumers on January 15, 2012

Rare is the public announcement that a long-standing medical recommendation has been found to be impossible to follow. That’s what happened—albeit unofficially— at a recent press briefing when Richard Kahn, PhD, announced that weight loss is not the sure-fire preventive measure for avoiding diabetes 2. Studies show that hardly anyone can lose enough weight to meet the universally recommended goal. And even those who get there halfway usually regain the weight within a few years.

That won’t come as a surprise to anyone has ever tried dieting. What made this press briefing noteworthy, however, is the fact that Dr. Kahn was the chief scientific and medical officer of the American Diabetes Association for 25 years. His study raises questions about the centerpiece of the ADA’s standard diabetes prevention message: “Maintain a healthy weight “(along with increased physical activity). This is the advice that is also given to people diagnosed with prediabetes, a newly created “disease” that indicates they almost have diabetes 2 (more on that later).  According to the ADA, which receives funding from the pharmaceutical industry, there are 79 million Americans who have prediabetes. All are likely to be put on long-term drug therapy once the weight-loss attempts fail or never get off the ground.

At the press briefing, Dr. Kahn, now a professor of medicine at the University of North Carolina, Chapel Hill, described his paper in this month’s issue of the public policy journal Health Affairs, which is primarily devoted to diabetes.  He has based his conclusion about weight loss on the very clinical trials that set the standard for diabetes prevention. Perhaps Dr. Kahn is the first to notice that most of the study participants, all of whom were initially either overweight or obese, regained the weight after the trials were over.

“When you look at the published studies, you see that a substantial amount of weight loss is necessary and hardly anyone can meet the intended goal, explained Dr. Kahn.  “People who participate in the standard community weight loss programs lose about 3-4% of their body weight, but they don’t get an appreciable delay in the onset of diabetes until they reach 7.5% weight loss. So you see they are not coming close to delaying or preventing diabetes.”

Based on the best of the diabetes prevention trials, here’s an estimate from Dr. Kahn’s paper for what a 4% weight loss would actually do for people in terms of health and cost-effectiveness: “If overweight or obese people could maintain for life a 4% reduction in weight at minimal financial cost, there would be a modest 1% reduction in heart attacks and strokes after 20 years. Rates of some microvascular complications [e.g., blindness, neuropathy, foot amputations] would also decline, but it would take at least 20 years—during which time weight loss was continuously maintained—for such an intervention to achieve cost-effectiveness.”

Dr. Kahn was the only author at the press briefing whose paper was not favorable to prevention. Several promoted a nationwide diabetes prevention program. “This would be a waste of resources,” said Dr. Kahn. “Instead we need a better understanding of the biological processes that cause so many people to put on weight.  I don’t think we know enough about energy balance, specifically energy intake vs. energy expenditure. Our bodies regulate that very, very closely, and we just don’t know enough about the components of that [process], or why this imbalance occurs in some people and not others. We eat all the time, food is all around us, food is cheap and maybe our bodies can’t adapt to this environment.”

Until obesity researchers come up with answers, drug therapy is the way to go once diabetes develops, according to Dr. Kahn’s paper,  “We can greatly reduce the likelihood of serious complications through early detection and proper medical management.” (Novo Nordisk, the company that makes diabetes drugs, was thanked by the editor of Health Affairs for partially funding this month’s issue.) However, Dr. Kahn expressed reservations about putting people on drug therapy when they are diagnosed with prediabetes,  “The use of metformin or other glucose-lowering medications might help prevent diabetes, but initiating such therapy prior to the onset of diabetes is basically equivalent to diagnosing the disease at a lower glycemic [i.e., blood sugar level] threshold and therefore deserves more discussion.”

Additional  information about prediabetes and exercise

More and more physicians have begun to treat prediabetes with drug therapy, though there is no evidence to show that this is safe or effective.  One can see tacit support for this practice on the ADA website which states, “Before people develop type 2 diabetes, they almost always have prediabetes—blood glucose levels that are higher than normal but not yet high enough to be diagnosed as diabetes.”  Read this about the pharmaceutical industry’s role in expanding the definition of diabetes 2 and why the current threshold for starting drug therapy is dangerously low for people with diabetes 2.  click here   And this about exercise, “You can be fat and fit.” 

Maryann Napoli, Center for Medical Consumers©

8 Responses to “Weight loss won’t prevent diabetes”

  1. Nancy Ashley said

    It’s called conflict of interest for a reason — why would it be in the interest of the ADA to promote weight loss since it would mean losing a lot of patients?

    As long as the ADA recommends diets full of fat, processed food, and animal products, the only way to achieve weight loss is through calorie restriction, which is almost impossible to maintain, I agree. But, the fact is that for people who are truly motivated to lose weight basic principles have been proven to be effective: a low calorie density, plant-based diet that avoids processed foods, saturated fat, trans fat, animal protein, and added oils is essentially guaranteed to cause sufficient weight loss to reverse diabetes. The beauty is that this same diet also reverses heart disease and a host of other lifestyle illnesses caused by obesity and overweight.

    If people aren’t given the tools to succeed, it is unlikely that they will.

    • I think you missed the point of the Dr. Kahn’s paper. He notes that all the people in the diabetes 2 trials were highly motivated (as demonstrated by their decisions to volunteer for weight-loss diabetes 2research). All lost some weight but regained it after the trials were over. In other words, they were given the “tools to succeed” but they didn’t succeed.

  2. dlr said

    How about an update on the “You can be fat and fit” article? I expect there has been a fair amount of additional research on exercise and health since 2008.

    Since exercise seems to be one of the few things people can currently do to actually improve their health, an unbiased overview would be extremely helpful.

  3. Richard Kahn said

    ADA publishes its Guidelines every year in a Supplement to its journal Diabetes Care. The Supplement lists, at the end, all the members of the Committee that produced the Guidelines and for each person, their “Conflicts ” are listed. Moreover, all guidelines published in between the production of the annual Supplement contain the disclosures of the group that produced them. It is, indeed, common for the best and brightest to also advise industry as it works to develop new drugs or understand how best to conduct studies on existing drugs. Everyone wants the best people to help them, and that is also true for the Associations who produce guidelines. I don’t think anyone wants opinions by non-experts. The goal, however, is to disclose everyones relationships with industry, and readers can make the judgment whether, on balance, the experts were not biased. Again, in my years at ADA we went to great lengths to be sure to have a wide diversity of experts on our Guideline group, we obtained advice from experts with no obvious preconceived opinions, and we had no input from industry. The widespread adoption of ADA guidelines is a testament to our objectivity.

    • Thank you, Dr. Kahn, for guiding me to the supplement. As you said, the experts who served on ADA guidelines committees did disclose their conflicts of interest and this information is available on the Web. Of the 18 experts on the committee, 12 reported that they had conflicts of interest, such as serving on the board of a drug company that makes diabetes drugs, owning patents and/or receiving consultancy fees from drug companies that make diabetes drugs. (Re the last example, some of the experts received consultancy fees from several drug companies but an asterisk appears only when the expert got more than $10,000 from the same company). I’ll leave it to our readers to decide whether this is a testament to the ADA’s objectivity. The disclosures can be accessed at

  4. Richard Kahn said

    I think what you failed to mention, which is in my paper, is that some people can lose a substantial amount of weight and keep it off for life . So it’s not “impossible”. The question was whether a substantial proportion of the population (e.g. > 40%) can do that , and community lifestyle prevention programs have not been that successful. But for those who do lose the weight, the benefits are tremendous–a 15-20% reduction in the risk of a serious complication from diabetes or dying from diabetes. Not, as you say –1%. Also, your article implies that its not worth even trying–which is not my recommendation. I believe people should try to lose weight, but appreciate the difficulty and enlist a lot of support from family and friends. Finally, in my 25 years at the American Diabetes Association, the pharmaceutical industry had no influence whatsoever in establishing any guideline or standard developed by ADA. R. Kahn

    • Your paper made substantial weight loss seem impossible to me. So did the clips from the press briefing I watched on Medpage. Re the 1% statistic that you say is incorrect, it is accurately quoted from your paper, see page 3 (unfortunately, the Health Affairs journal made it clear that I cannot post the entire article). Re pharmaceutical industry influence on the establishment of treatment guidelines: Too often the experts selected for guidelines panels have extensive financial ties to drug makers, for example, consulting fees, grants, etc. Put that together with the fact that the definition of several diseases, including diabetes 2, has been expanded in the last 15 years, often making millions more Americans into potential drug customers. Here’s a study that looked at experts who served on treatment guidelines committees for organizations in the U.S. and Canada. The study found that conflicts of interest (COI) among panel members are common in guidelines issued by certain specialty organisations. The prevalence and underreporting of COI are high and transparency is incomplete among a wide range of guideline producing organisations.” The ADA was one of the organizations in this study. After reading it, I looked up ADA treatment guidelines 2011, but I could find no conflict of interest disclosure statements for the experts who serve on the panel. Perhaps you can help me locate them.

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