Gina Kolata reports on a surprising result for a long-term study of diet and exercise in the treatment of type 2 diabetes: "Diabetes Study Ends Early With a Surprising Result".From the New York Times via John Hawks.
The study randomly assigned 5,145 overweight or obese people with Type 2 diabetes to either a rigorous diet and exercise regimen or to sessions in which they got general health information. The diet involved 1,200 to 1,500 calories a day for those weighing less than 250 pounds and 1,500 to 1,800 calories a day for those weighing more. The exercise program was at least 175 minutes a week of moderate exercise.But 11 years after the study began, researchers concluded it was futile to continue — the two groups had nearly identical rates of heart attacks, strokes and cardiovascular deaths.One expert quoted in the article thinks that the large effects of smoking cessation, statin drugs and blood pressure medications may swamp the small effect of diet and exercise. Swamp the small effect of diet and exercise on type 2 diabetes in obese patients? Wow.
Another recent study linked in my previous post at this blog today (actually two) notes that exercise programs are ineffective at treating juvenile obesity in practice. Those studies are:
- B. Metcalf, W. Henley, T. Wilkin. Effectiveness of intervention on physical activity of children: systematic review and meta-analysis of controlled trials with objectively measured outcomes (EarlyBird 54). BMJ, 2012; 345 (sep27 1): e5888 DOI: 10.1136/bmj.e5888
- M. Hamer, A. Fisher. Are interventions to promote physical activity in children a waste of time? BMJ, 2012; 345 (sep27 1): e6320 DOI: 10.1136/bmj.e6320
Both rigorous diet programs and exercise programs are very challenging in the lives of participants, so recognizing their limited effectiveness, despite all logic that says that these programs should work, is essential. It should at least provide some solace to people who have tried these approaches without getting results to know that they are not alone.
Empirical evidence regarding what actually does work is better than a completely solid theory regarding what should work any day. And, in the area of treating obesity, reason and experience are very much at odds. Why this is the case is hard to tell, but it is the reality.
One can't simply do large scale experiments, in the case referenced by Hawks for eleven years, and ignore the fact that some treatment modalities, for whatever reason, don't work.