On March 7, 2007 – Just as my book was rolling off the press, a new study comparing four different diets was published in the Journal of the American Medical Association (JAMA 2007; 297: 969-977). All the major news sources featured headlines reflecting their own particular bias: “This Proves Atkins is Best Diet” said the London Times; the Seattle Times reported “Study: Women lost a bit more with Atkins.”
The scientists who designed the study expressed surprise that the Atkins diet came out on top with an average loss of 10 pounds in a year and no adverse effects. I too was surprised at the results—not that low carb was the best of the diets tested, anyone who has tried it already knows that. What surprised me was that the difference was so small. I would have expected a loss of 50 to 100 pounds if the subjects were actually following a low-carb lifestyle.
I can suggest several possible explanations for the modest, but significant, difference the study discovered in the comparison:
The women assigned to the Atkins regimen did not actually follow the Atkins plan. According to Dr. Michael Eades, who analyzed the charts in the report, they ate 61 grams of carbohydrate per day for the first two months and then went up to 140 by the end of the study. A far cry from the 20 and 50 specified as the target amount for the two phases. On a true Atkins plan, they would have increased their carb intake in small increments in order to discover how many they could tolerate. Some may have needed to stay at a lower number while others could handle more.
Once the participants were on their own, they all gained weight, but the low carb group had an additional disadvantage. If you check out the offerings at any typical grocery store or restaurant, you find many low fat and low calorie choices, but it is almost impossible to find low carb products, especially since there is so much sugar hidden in unexpected places. I recently bought a package of fresh pork chops from the meat counter. It never occurred to me to check the nutrition label. As I was putting it away, I noticed the carb count. Every trace of fat had been trimmed away, but the meat had been injected with sugar. When pork is bred to be as lean as possible (the other white meat), it will be tough and dry—they shoot it full of sugar to make it taste better.
The report stated that compliance was not good in any of the groups, and although it was better for the Atkins faction, low-carb diets are fundamentally different from others. Carbohydrates cause the pancreas to secrete insulin. Insulin is required to store fat—so eat fewer carbs—store less fat. But each person has a specific upper limit beyond which this metabolic advantage is lost. A few calories more or less won’t have much effect on a low-calorie regimen, but on a low-carb plan, if you exceed your critical number, you will produce enough insulin to cause weight gain. I once asked my scientist husband to define the word “quantum” for me. In trying to put it in words I could understand, he said, “nothing happens, nothing happens, nothing happens, everything happens!” That describes the result of just a few extra carbs on a diet that allows unlimited calories.
There is another factor that is usually not mentioned when summarizing the different diet studies. Low carb dieters never have to experience hunger since they can eat as much as they like. It is the quality of the food and not the quantity that counts. And while exercise is a good thing, it is not essential for weight loss. This has been proved many times by people who were too heavy or too sick to be able to do it. Most of the other systems limit portion size and total calories and require a lot of sweat as well. Then if you fail to lose weight, they can say it is your own fault for not working hard enough!
Every time a study that validates low-carb as an effective way to lose weight and reduce health risks is reported in the media, you will find several quotes warning that this diet has not been tested for long periods of time and that it may prove to be unsafe after 20 or 30 years. But, hey, we’ve been testing the low-fat diet (which was never based on scientific evidence) on Americans for 30 years now, and you only have to look around to see how effective that has been!
If this study really compared a low carb diet to all the others out there, it would have beaten the pants off the competition.