The diet wars are back. A new study, funded by the National Institutes of Health and published in the Journal of the American Medical Association, compares four diets: Atkins (very low carbohydrate, high fat), LEARN (low fat), Ornish (very low fat), and the Zone (low carb). The participants were 311 fat women aged 25 to 50, randomly assigned to one diet or another. According to the Wall Street Journal, women on Atkins “lost the most weight. But there’s one catch—the women didn’t really stick to the diet.” The study’s lead author, Christopher Gardner of Stanford University, concludes: “Is this a vindication of Atkins? No, because they weren’t really following Atkins.”
Now, wait a muffin-pickin’ minute. There are plenty of caveats worth noting about this study. But the fact that participants didn’t stick to their regimens, as the diet gurus who lost to Atkins are pointing out in every available forum, isn’t one of them. Unless you plan on jailing people and sliding food under the door, their ability and willingness to adhere to your diet are crucial factors in its effectiveness. If they’re too weak or stupid to follow the formula, stop telling them to buy it.
According to the study, “Weight loss was greater for women in the Atkins diet group compared with the other diet groups at 12 months, and mean 12-month weight loss was significantly different between the Atkins and Zone diets.” Furthermore, “At 12 months, secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups.” In short, Atkins did no harm and slightly more good.
The study has its shortcomings. If you aren’t female, fat, and 25 to 50, the findings may not apply to you. The average weight loss in the Atkins group was only 10 pounds, so the differences among diet outcomes were small. The study lasted only a year, so it didn’t measure weight gain or health problems down the road. Nor did it measure effects on kidneys, bone density, or cancer. All four groups regained some weight in the second half of the year, and according to the authors, the trends “suggest that longer follow-up would likely have resulted in progressively diminished group differences” among the diets.
The participants clearly cheated. In theory, Atkins restricts you to 50 grams of carbs a day. By the study’s end, the average Atkins dieter was nearly tripling that. The Zone tells you to get 30 percent of your calories from protein and only 40 percent from carbs, but the average Zone dieter never met the protein quota or obeyed the carb limit. Ornish forbids you to get more than 10 percent of your calories from fat, but the Ornish dieters tripled that. LEARN dieters ate 20 percent of their calories in the form of saturated fat, twice what they were supposed to. This, mind you, is what the participants admitted in phone interviews. Imagine how much more they concealed.
The losing gurus have pounced on this, arguing that it discredits the study. “People didn’t really follow the diet I recommend,” complains Dr. Dean Ornish, founder of the Ornish diet. Of Atkins, he sniffs, “It’s a lot easier to follow a diet that tells you to eat bacon and brie than to eat predominantly fruits and vegetables.” Dr. Barry Sears, architect of the Zone diet, scoffs that “what the subjects ate in the JAMA study had no relationship to any of the diet programs that were supposedly being tested. … In fact, the amount of carbohydrates consumed on the ‘Atkins Diet’ during the study was almost identical to the recommendations of the Zone Diet, which explains why ‘Atkins’ had the most favorable results.” Sears maintains (subscription required), in the Journal’s words, that “to really understand which diet is most effective, the eating plans need to be studied under highly controlled conditions.”
But that assumption is exactly what the study rejects. People don’t live in highly controlled conditions. They live in the real world. They forget things. They miscalculate. They’re tempted. They rationalize. You can’t test a diet by screening out these failings. You have to incorporate them. What gives the study “external validity,” the authors explain, is that it assesses food consumption “under realistic conditions.”
In the real world, simplicity helps. Atkins has few rules and “one of the simplest messages … absolutely no sugar and no refined carbs,” Gardner observes. That, he suspects, might explain why participants followed the Atkins regimen more closely than the other diets.
In the real world, sometimes you have to push people too far to get them to go halfway. “Cutting back drastically on simple carbohydrates,” as Atkins demands, “is clearly a step in the right direction,” says Gardner. Contrary to Sears’ complaint, the prescribed diets did affect what participants ate. The Atkins group cut its carb intake by more than half. No other group came close to that. If it’s true, as Sears protests, that the only participants who lowered their carbs to Zone levels were those assigned to the more extreme Atkins diet, then which of the two diets would you recommend to a friend? I’d go with Atkins.
In the real world, wise policies admit and work with human weakness. Capitalism uses greed to spread wealth. Political checks and balances use ambition to check ambition. Atkins uses meat and fat cravings to kill appetite. As Gardner explains, “Protein is more satiating than carbohydrates or fats, which may have helped those in the Atkins group to eat less without feeling hungry.” Complaining that people follow Atkins only because it’s tasty is like complaining that businessmen create jobs only to get rich. A job is a job.
I know it seems crazy that sausage and cream cheese could be good for you. In the long run, I’m certain they can’t be. But the beauty of science is its disrespect for certainties. You play the game and see who wins. In the short run, so far, Atkins wins.
The ideal diet, I’m sure, is Gardner’s. He’s a vegetarian. I’d be one, too, if I had the strength. And the ideal birth-control method would be abstinence, if we could all be chaste. But until people are more like angels, you’d better deal with us as we are, or be prepared to share in the failure.