Already-confused dieters are no doubt reeling from reports this week of a new study linking a high-carbohydrate diet (search) with weight loss.
Rather than well-conducted scientific research, though, the new study appears to be merely a junk science-fueled attack by government nannies on politically incorrect low-carbohydrate regimens like the Atkins Diet (search).
“In the midst of the low-carb craze, a new study suggests that by eating lots of carbohydrates and little fat, it is possible to lose weight without actually cutting calories ― and without exercising, either,” reported The Associated Press this week.
“Revenge of the High-Carb Diet ― Ha! It Works, Too” was the Reuters headline.
But unlike the sensationalistic media, which tend to limit their reporting of new study claims to regurgitated press releases and sound bites from study authors, I actually read the study in the Jan. 26 issue of the Archives of Internal Medicine.
It didn’t take long to discover why study subjects on the high-carbohydrate diet lost weight ― they ate fewer calories!
The researchers divided the 34 study subjects into three groups: a control group of 12 individuals who consumed a low-carbohydrate diet (search); a group of 11 individuals who consumed a high-carbohydrate diet; and a group of 11 individuals who consumed a high-carbohydrate diet and did aerobic exercise.
Study subjects were provided with foods constituting 150 percent of their required daily caloric intake and instructed to eat as much as they wanted. Carbohydrates constituted 45 percent of the control groups’ calories and about 62 percent for the high-carbohydrate groups.
After 12 weeks, the study subjects on the control diet weighed the same as when the study started. But study subjects on the high-carbohydrate diet lost weight: about five pounds on average for those in the high-carbohydrate-only group and about 10 pounds for those in the high-carbohydrate-plus-exercise group.
To the study authors and media, these superficial “results” apparently prove that you can lose weight while eating as many carbohydrates as you like ― and you don’t even have to exercise.
It might be a couch potato’s fantasy come true ― except that the study details tell a different story.
As it turns out, study subjects in the high-carbohydrate groups consumed about 400-600 calories less per day than those in the control group. Over the 12-week period of the study, then, the average study subject in the high-carbohydrate group consumed about 42,000 calories less than the average study subject in the control group.
Since a pound of fat represents about 3,500 calories, it’s no wonder why those in the high-carbohydrate group lost weight. It was because they ate less, not because of any magical effects of a high-carbohydrate diet.
Although the media’s apparent lack of interest in examining the actual study data is disappointing, the inaccurate description of the study to the media by lead author William J. Evans of the University of Arkansas for Medical Sciences is even more dismaying.
He told Reuters that the study subjects ate “around 2,500 calories per day,” thereby implying that the only difference in their diets was the amount of carbohydrates. That’s just plain misleading.
Control group subjects averaged 2,825 calories per day during the 12-week study; high-carbohydrate group subjects averaged 2250 calories per day and high-carbohydrate-plus-exercise subjects averaged 2,413 calories.
Such variation over 12 weeks adds up to significant differences in total caloric intake and is most likely what produced the observed weight loss in the high-carbohydrate groups.
The study authors then had the audacity to slam low-carbohydrate diets, such as the Atkins diet, as a means to lose weight.
“Little evidence exists to support this idea,” wrote the study authors.
But it appears that there’s not even that much evidence in favor of their all-the-carbs-you-can-eat idea.
It’s no secret that nutrition nannies in the federal government oppose high-protein/low-carbohydrate diets like the Atkins plan ― not because such diets don’t work but because their fat-is-OK approach contradicts the nannies’ low-fat dietary prescriptions of the last 30 years. (The irony of course is that obesity has supposedly skyrocketed while America went low-fat.)
Evans and his group, not surprisingly, were funded by the National Institutes of Health, a government group that claims in bold-face on its Web site that “[High-protein/low-carb diets are] not a healthy way to lose weight!”
That may or may not be true. Much more research is needed. Hopefully that research won’t be conducted by biased, government-funded research hacks.
Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-Defense Against Health Scares and Scams (Cato Institute, 2001).