Marvin Moser, MD, Editor in Chief

Journal Clinical Hypertension 4(5):322-324, 2002.
© 2002 Le Jacq Communications, Inc.

Posted 10/30/2002

Introduction

On July 7, 2002, science writer Gary Taubes, in a cover story in the New York Times Magazine elaborated on the benefits of the Atkin's diet -- a high-fat, low-carbohydrate diet that includes virtually no fruits, grains, or milk products, and only a small amount of vegetables. He strongly suggested that this was not only an effective diet to lose weight but was healthier than the commonly recommended low-fat diet that included other food products. We must assume that by "healthier" he meant that it would help reduce the occurrence of cardiovascular diseases. Confusion reigned; what and whom should people believe?

The article represented a biased refutation of previously recommended diets by the American Heart Association and a large majority of nutritionists and scientists in the United States over the past 20 years. Taubes noted that the "establishment" did not accept the idea that a diet high in fat was healthy. This may be true, but the "establishment's" recommendations for a lower fat intake had not been picked out of thin air. It was based on numerous epidemiologic studies that had demonstrated the highest incidence of coronary artery disease in populations that consumed large amounts of high-fat foods. In Finland, South Africa, and Eastern Europe where diets are high in fatty meats or dairy products, the incidence of coronary heart disease is higher than in countries where the diet is lower in these foods. In addition, animal data, as well as some clinical trials that have been reviewed and published in peer review journals, have reported that diets low in fat will help reduce the occurrence of coronary artery disease.

Mr. Taubes claimed to have researched his facts carefully. But just as a scientist who throws out the three or four cases out of 20 that do not conform to his preconceived assumptions prior to an experiment, this writer dismissed the opinions of anyone who, in his judgment, was deemed to be a "poor scientist." He continually stressed that the epidemic of obesity in the United States and the increased incidence of type 2 diabetes was the result of people reducing the amount of fat in their diet and increasing carbohydrate intake. He appeared to blame this on recommendations of national committees. A diet excessively high in carbohydrates may be a villain in the epidemic of obesity but scientific evidence indicates that obesity is a result of the intake of too many calories, whether they are from proteins, fats, or carbohydrates. Calories do count!

In a critique of Mr. Taubes' article, Sally Squires of the Washington Post, on August 27th carefully outlined in great detail the results of her investigation. She notes that several of the individuals interviewed by Mr. Taubes were never quoted. She cites specific instances. One of these is Dr. Xavier Pi-Sunyer, who is on the faculty of the Institute of Human Nutrition at Columbia University and has served as President of the American Diabetes Association. He had published a summary of clinical trials on low-fat diets, which concluded that reducing dietary fat can help promote weight loss by reducing calorie intake and that this is a practical approach to the problem of obesity. Mr. Taube concluded "anything that Dr. Pi-Sunyer was involved in I don't take seriously. He just didn't strike me as a scientist." When other studies suggested benefit from a low-fat diet, he considered them flawed. On the other hand, he goes to great lengths to quote numerous people who shared his opinions but who are short on good scientific data to advance the "high-fat is healthy" concept. Where are the studies of Dr. Atkins, the guru of the high-fat diet? Where are the results of long-term evaluations? There are none! Dr. Atkins claims that he has never had any support for long-term studies. It is apparent, however, that the income from the literally hundreds of thousands of his books that have been sold could adequately support any long-term evaluation at least of his own patients. How many of them experience adverse effects on lipids with a high-fat diet; do they live longer; are they experiencing less or more cardiovascular disease? This type of study does not require millions of dollars as Dr. Atkins claims.

Many years ago we had two patients who had been on the Atkins diet and had, as others have, experienced a definite weight loss. Cholesterol levels had risen to >300 mg/dL. After many attempts, we were able to contact Dr. Atkins whose answer to this information was "none of my patients have an increase in cholesterol levels on my diet." Where are the long-term data to substantiate this? There have been several articles about the benefits of a high-fat diet. There is little doubt that patients lose weight, but it is a weight loss generated by fewer calories; people on high-fat diets may lose their appetites. These studies suggest that there are some people whose low-density lipoprotein (LDL) levels increase, some that do not, and some, probably as a result of the weight loss, whose LDL levels decrease. But no good data exist on the long-term effects on cardiovascular disease of a high-fat weight loss program compared to a balanced-diet weight loss program.


Why Has the Debate Become So Acrimonious?

Many years ago the American Heart Association and several other national committees suggested that people go on a low-fat diet. It was noted, for example, that people should drastically reduce their intake of eggs because each egg contained more than 210-225 mg of cholesterol and the low-fat diet suggested that total intake should not be more than 250-300 mg per day. It was suggested that meat should only be eaten two or three times a week and then only low-fat meats. Some people rebelled just the way they did when they were told that in order to carry out an aerobic exercise program they had to jog or run and build up a certain "number of points" per week. Many people found that they couldn't jog or run several times a week, that it caused joint trouble, that they were bored, or that they were easily fatigued. Many decided that since they couldn't do what the experts recommended, they wouldn't do anything. Recommendations changed; it has been shown that rapid walking or any other enjoyable aerobic or motion activity for 45-60 minutes a day is adequate to reduce cardiovascular risk. The pendulum had swung back to a practical and doable approach without minimizing the benefit.

Similarly, people reacted to the rigidity of the national recommendations on dieting. These recommendations have been modified. People can have eggs several times a week and roast beef, a steak, or even chocolate cake and still keep fat calories at less than 25% of total intake.

People may have also reacted to the fact that an elevated cholesterol level would not necessarily be reduced if a tolerable reduced fat intake were followed. This is true in many cases; cholesterol may not be reduced by more than 10%. For example, a reasonable diet that could be followed may only reduce a 280 mg/dL cholesterol to 250-260 mg/dL. A marked weight reduction program and elimination of practically all fat (10% or 15% of calorie intake as fat) might lower cholesterol levels considerably more. But this type of diet is impractical except in highly motivated people. This lack of achievement on the diets recommended by the American Heart Association led many people to conclude that low cholesterol, low-fat diets do not work and led to the reaction pointed out in the Times article, which was titled "What if it's all been a big fat lie?" Certainly not a lie, but perhaps an overzealous attempt on the part of some scientists to change habits and to alert people to the possible dangers of a high-fat intake.


Hypertension and the High Fat Debate

Why is this debate germane to patients with hypertension? More than one-third of patients with high blood pressure also have other risk factors for heart disease. The most common of these include dyslipidemia (elevation of LDL levels), oftentimes a low high-density lipoprotein, and an elevation of serum triglycerides. In addition, many are obese and have insulin resistance. They are candidates for type II diabetes. Mr. Taube claims that one cause of the epidemic of obesity and type II diabetes is the national obsession to avoid fatty foods and increase carbohydrate intake. The facts state otherwise. No one has advised anyone to increase his or her calorie intake by eating more. Recommendations have suggested a balanced diet with less fat and, if anything, fewer total calories.

The marked increase in obesity has occurred for several reasons, not because of national recommendations. Children are exercising less and burning fewer calories; they don't walk to school as often; many schools have discontinued gym classes; sports are organized (if you are not a participant, you are not exercising enough). Importantly, those 600 calorie French fries, 1000 calorie burgers, pizzas, etc., are contributing to an average increase in intake of more than 400 calories a day. These foods taste good and are affordable, but they are major contributors to the fat adolescent. It is well known that, in most cases, an obese adolescent becomes an obese adult (an increase of 400 calories a day in intake without an increase in exercise [calorie burning] may lead to almost one pound a week weight gain).

Omitted in the Times article is the fact that at least part of the increase in the occurrence of type II diabetes may be that the definition of diabetes has changed. Several years ago a blood sugar of up to 140 mgs/dL was considered within normal limits. Diabetes is now diagnosed if blood glucose levels are above 126 mg/dL. Naturally, the numbers of diabetics has increased. While some of the increase may be due to the increasing numbers of obese people, the change in definition must account for a portion of newly diagnosed cases.

As noted, it has been repeatedly emphasized in the management of hypertension that other risk factors should be reduced at the same time that blood pressure is lowered. Obesity is a major factor that should be modified.

Weight reduction is clearly the most important nonpharmacologic approach to the lowering of blood pressure. Increased exercise plus a reduction in calories have been shown in repeated studies to result in weight reduction. Perhaps this is not accomplished as rapidly as with a high-fat, low-carbohydrate diet, but over time it may prove to be a more healthful approach. Data from both population studies and clinical trials suggest that this approach is effective but takes time. Extreme radical dieting, whether by means of a low fat or high fat, protein or carbohydrate diet (and people have tried them all) has never proved to be the answer to long-term weight loss or decreasing the risk of cardiovascular disease.


Where is the Proof That a High-Fat Diet Is Safe and Reduces Risk?

If Dr. Atkins and other advocates of the high-fat approach to reducing weight and cardiovascular risk are so certain that this method is safe and effective, let them allow an independent group of investigators to review their records over the last 15 years to determine exactly what happened to their patients. Let's replace popular best-selling book theories with scientific fact and have journalists report the "rest of the story" -- not their personal bias. There is little doubt that patients lose weight but there is no scientific proof that this type of weight loss from a high-fat regimen is beneficial over time in reducing cardiovascular disease -- and perhaps it may be harmful. Let us also not forget that a high-fat diet has also been linked to increases in some forms of cancer.

The retreat from rigid national guidelines is not unexpected, but it is hard to believe that the unbalanced opinions of the Times July 7th article have apparently been so widely accepted. As Sally Squires noted, the Atkin's book jumped from No. 5 to No. 1 on the Times advice books bestseller lists and from No. 170 to No. 5 on Amazon.com. In addition, the author has received an offer of $700,000 for a book.

The power of the press is well known and should be considered before an article with only one side of the story is published. This is done all the time with political reporting, and an opinion piece on the editorial page of a newspaper is appropriate, but health issues should be another matter.

Yes, it is easy to make money by taking a stand against the "establishment." That always seems to work. Yes, it is easy to make money by ignoring science and advancing unproven theories. That's easy. In this case, however, it is clearly up to the high-fat diet believers to present scientific proof that they are correct and the establishment is wrong. At present, we should continue to advise our hypertensive patients to lose weight and to exercise. A low-fat, low-calorie diet that includes a balance of proteins, carbohydrates, grains, fruits, and low-fat milk products is a reasonable proven approach. Rigidity is not the answer -- common sense is. Fat budgeting can be carried out and weight loss achieved without turning a household into a diet kitchen or possibly endangering your health.

http://www.medscape.com/viewarticle/443216