Dude! Joe's Jottings, Mostly Junk

The latest edition of the New England Journal of Medicine features research out of the Harvard School of Public Health and the Pennington Biomedical Research Center. Scientists monitored individuals for two years on one of four popular diets: low fat, high carb, high fat, and high protein. The results (drumroll please.....)

It's all about calories.

Go figure.

ABSTRACT

Background The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year.

Methods We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content.

Results At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels.

Conclusions Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.

I hate to be pessimistic, but I can't help what I notice. I've listened to economists on everything from NPR to CNN to Fox News to Keith Olbermann. The hosts like to ask a fairly obvious question of the economists they interview: how will we know if the stimulus worked or not?

And they never get a quantitative answer. Never.

Now I don't pretend to be an expert economist. But there are a lot of expert economists out there, some of whom are right at this very moment deciding on the disposition of trillions of my tax dollars. (Well, your tax dollars anyway. I'm poor, I don't pay much tax.) I'm a little concerned that none of them are willing to say anything like "If our current plan is accepted by congress and the president, unemployment at year's end will be between 6 and 8 percent, with GDP having contracted by 5%."

It's not quite what we're hearing.

"We're not making it up," Bernanke told the House Financial Services panel. "We're working along a program that has been applied in various contexts," he said. "We're not completely in the dark."

Maybe we're just spoiled in the physical sciences, but I don't think you'll read anything like that in Physical Review Letters.