Junkfood Science: Play it again, Sam

July 11, 2007

Play it again, Sam

Another study has examined the effectiveness of counseling to get people to eat healthier and exercise to lose weight. Guess what it found?

Researchers at Tufts-New England Medical Center in Boston, Massachusetts, examined 46 clinical trials of dietary counseling for weight loss, involving nearly 6,400 dieters. Regardless of the programs — the intensity of the interventions, number and frequency of support meetings, individual or group counseling, caloric or other dietary restrictions, inclusion of exercise, use of electronic media such as the internet, or level of participation — they all produced an average weight loss of about 6 percent during the first year..... And a steady regain every month after that. By the end of five years, the researchers said, all participants had fully regained their weight.

They also reported that the studies supporting various weight loss programs were generally of moderate to poor methodological quality, with high rates of missing data due to large numbers lost in followup, making the exact degree of their effectiveness difficult to specify. Even so, the programs proved universally unsuccessful in the end.

The long-term failure of every diet intervention might not be readily apparent to a busy medical practitioner just glancing at the abstract’s conclusions, though. It stated:

Compared with usual care, dietary counseling interventions produce modest weight losses that diminish over time. In future studies, minimizing loss to follow-up and determining which factors result in more effective weight loss should be emphasized.

The findings of this study are nothing new, of course, nor are the recommendations emerging from them.

The scientific reviews of the evidence on dietary counseling conducted by the U.S. Preventive Services Task Force in 1996 and 2003 concluded there is insufficient evidence to recommend routine counseling by healthcare professionals to promote a healthy diet in adults.

So maybe more is better? No. The USPSTF found the evidence fair to good only that high-intensity counseling among patients with specific diet-related diseases, together with behavioral interventions aimed at skill development, motivation, and support strategies, produced modest, weight loss for the first year. But, they said, the evidence could not point to effective interventions for the general population. The evidence for intense interventions among these high-risk groups still demonstrated only modest short-term changes, with no information on actual health benefits and insufficient evidence to recommend widespread dietary counseling. Nor did they address possible adverse effects of dieting and inevitable yo-yo dieting, which are well-recognized in the medical literature.

What did the researchers of this latest study recommend to doctors?

“Primary care doctors should take a more active role in seeing patients more regularly for lifestyle management,” said lead author, Dr. Michael L. Dansinger.

In other words, it doesn’t work, so keep doing it, but try harder.

But when that fails, as everyone knows it will, their Center can offer a “long-term” solution. As their website says: “We’re proud to announce we’ve recently been designated a national ‘Center of Excellence’ by the American Society for Bariatric Surgery.”

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