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News coverage and commentary about studies of low-carbohydrate diets have generated a lot of attention, but they haven’t done an adequate job of putting the science into context for people seeking guidance for long-term health.

By Suzanne Havala Hobbs
December 3, 2003

It’s hard to resolve conflicting messages about low-carbohydrate, high-protein diets.

The news media report studies that suggest low-carb diets do a good job of helping people lose weight. Word of mouth seems to confirm that message. Almost everyone knows someone who has lost weight on a low-carb diet. Some say they’ve lost a substantial amount of weight.

Add all of the marketing for low-carb diet books and advertising for low-carb foods and it’s easy to conclude that there must be something to this low-carb craze.

But little rigorous attention has been given to questions about the long-term effects of low-carb, high-protein diets.

While it may be gratifying, and sometimes medically beneficial, to lose weight in the short term, most of us make life plans for the long term. None of us would choose to marry or have children based on goals set only six months into the future. Likewise, our diets should reflect our thinking about lifelong health and wellness objectives.

Many questions remain unanswered, but nutrition science has provided a great deal of evidence that can help guide people in making dietary decisions aimed at promoting long-term wellness, including weight control. Some of that evidence is based on studies involving tens of thousands of people followed for decades.

But the manner in which nutrition science news and information is conveyed to the public creates some hazards. News reporters are faced with the need to simplify complex scientific reports into easily accessible language. Deadline and competitive pressures sometimes demand that the job be done very quickly. The desire for public recognition and continued funding may spur some scientists and their institutions to seek the widest possible news coverage of research findings, even tenuous or preliminary ones.

Combined with other factors, it’s a mix that often leads to big-type headlines on stories that, on closer inspection, don’t quite measure up to initial impressions.

The result? Continued confusion about nutrition: what foods are good for you, what foods are not so good for you, what are the components of a sensible eating plan.

Much of the reporting and commentary available in the news media and other outlets, such as the Internet, concerning low-carb, high-protein diets has created confusion. Low-carb diet proponents emphasize the short-term weight loss that can be achieved with the diets. Mainstream nutritionists and physicians routinely criticize the diets, saying they may pose long-term dangers.

I don’t intend here to attempt to resolve that conflict. Instead, I want to provide you with some readings that illustrate that much of the news coverage and commentary about low-carb diets has been incomplete, and sometimes plain wrong, often creating situations that could easily cause consumers to make erroneous conclusions about low-carb diets.

The New York Times Magazine: “What if Fat Doesn’t Make You Fat?”
By Gary Taubes
July 7, 2002

This article, complete with a magazine cover photo of a fat-girded pork chop with a melting pat of butter on top, proved to be a turning point in fad dieting.

As I mentioned in my column, the article hinges on this sentence: “If the alternative hypothesis [that carbohydrates are what make us fat] is right – still a big “if” – then it strongly suggests that the ongoing epidemic of obesity in America and elsewhere is not, as we are constantly told, due simply to a collective lack of will power and a failure to exercise.”

The article is no longer available for free on The New York Times website, but has been reprinted in full on the Atkins Nutritionals, Inc. website here. It’s long. If you care to engage in the exercise, I invite you to read it carefully. Despite the length, you’ll find no point-blank statements that low-carb dieting has been proven safe or health-promoting.

Sally Squires of The Washington Post wrote this Aug. 23, 2002 article, entitled “Experts Declare Story Low on Saturated Facts,” for which she interviewed Taubes and dozens of researchers, including many of those Taubes interviewed. Squires says her reporting showed that some of Taubes’s key assertions in The New York Times “are contradicted by a significant amount of high-quality research.”

After Squires’s story ran, Taubes objected to Squires’s use of many of his quotes, saying the two had an agreement that he would have the opportunity to approve any quotes before they ran in the paper, according to this article in the Columbia Journalism Review.

“Efficacy and Safety of Low-Carbohydrate Diets”
Research paper in the Journal of the American Medical Association
By Dena Bravata, MD, of Stanford University, and others
April 9, 2003

This project aimed to review all English language research on low-carbohydrate diets published between 1966 and February, 2003 to evaluate the diets’ effectiveness in promoting weight loss and effects on cardiovascular-health markers and blood pressure. The project scrutinized 107 articles that involved 3,268 study participants. Only five studies followed patients for more than 90 days.

The paper’s conclusion: “There is insufficient evidence to make recommendations for or against the use of low-carbohydrate diets, particularly among participants older than 50 years, for use longer than 90 days, or for diets of 20 [grams per day] or less of carbohydrates. Among the published studies, participant weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration but not with reduced carbohydrate content.”

The abstract, the researchers’ summary of their article, is available here.

“A Randomized Trial of a Low-Carbohydrate Diet for Obesity”
By Frederick Samaha, MD, of the Philadelphia Veterans Affairs Medical Center, and others
“A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity”
By Gary Foster, PhD, of the University of Pennsylvania, and others
Both papers were published in The New England Journal of Medicine
May 22, 2003

These papers made a big news splash when they were published, generating headlines such as this from the Associated Press: “Pair of Studies Vindicate Atkins Diet.” But they also generated this headline from Reuters: “Atkins Diet May Be No Better Than Just Cutting Fat.”

The Samaha study randomly assigned 132 severely obese people to either a carbohydrate-restricted diet or a low-fat diet for six months. Seventy-nine people completed the six-month study.

The Samaha study abstract’s conclusion: “Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels, even after adjustment for the amount of weight lost. This finding should be interpreted with caution, given the small magnitude of overall and between-group differences in weight loss in these markedly obese subjects and the short duration of the study. Future studies evaluating long-term cardiovascular outcomes are needed before a carbohydrate-restricted diet can be endorsed.”

The Samaha abstract is available here.

The Foster study followed 63 obese patients for one year, with half assigned to either a low-carb, high-fat and high-protein diet and half assigned to a conventional low-calorie, high-carb, low-fat diet. Patients on the low-carb diet lost more weight at the three-month and six-month points, but at the end of a year there was little difference in weight loss.

The Foster study abstract’s conclusion: “The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year. The low-carbohydrate diet was associated with a greater improvement in some risk factors for coronary heart disease. Adherence was poor and attrition was high in both groups. Longer and larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.”

The Foster abstract is available here.

Here’s how Atkins Nutritionals, Inc. described the studies on its website:

“Two More Studies Validate the Atkins Nutritional Approach
For the last 30 years the common wisdom has been that a low-fat regimen is the only way to achieve good health and weight control. The results of the studies reported in the May 22, 2003, issue of the New England Journal of Medicine add to the growing body of evidence supporting the low carbohydrate approach and are consistent with other recent trials comparing Atkins to low fat. In both studies headed up by Gary D. Foster, Ph.D., and Frederick F. Samaha, M.D., the Atkins participants lost more weight and showed greater improvements in cardiovascular risk factors than did the low fat participants. Considering that the epidemic of overweight and obesity has increased to an alarming 64.5 percent during the time when low fat was the predominant recommendation, these significant results should make physicians and the rest of the health care community more comfortable recommending the low carbohydrate alternative to their patients.”

Note the absence of any discussion about results after one year. Also note the conclusion that physicians should be “more comfortable” recommending low-carb diets and how that compares with the researchers’ calls for more study.

The Reuters story on the studies is available here.

The Associated Press story on the studies has been posted here. Read the story carefully with the headline “Pair of Studies Vindicate Atkins Diet” in mind. You’ll see that one researcher says there’s still not enough evidence to endorse low-carb diets. Another says that there wasn’t much difference in weight loss between low-carb dieters and low-fat dieters after one year. Then, a spokeswoman from the American Dietetic Association points out that the Foster study indicates that low-carb dieters have no better success than low-fat dieters at keeping weight off over time. Where’s the vindication?