Dear Reader #1 and Marianne in Mesquite, TX,

You are not alone — turn on the TV or read any newspaper or magazine, and you will be bombarded with weight loss information. It seems the more that's talked about this subject, the more confusing it becomes.

Researchers have begun to investigate whether it's healthier to follow a low carbohydrate eating plan (such as the Atkins diet) or a low-fat one. The results of one such study, conducted at the University of Pennsylvania, was published in the May 2003 New England Journal of Medicine. Dr. Gary Foster and his research team followed 63 obese men and women, who were randomly assigned to be on an Atkins-style low carb diet or a low-fat diet. Before the study was over, 40 percent of the participants dropped out, which shows how hard it is to stick with any diet! So, Marianne, it's not your fault — many diets fail us, rather than us failing the diet.

During Dr. Foster's study, by the 3rd and 6th month mark, the low carb group lost more weight than the low-fat one. At the end of the 12-month study, neither group regained all of their lost weight; however, the low carb group gained back more weight than the low fat one. The low carb group lost a little more weight in total, but the difference between the two groups was not statistically significant. After one year, the low carb group lost an average of 9 pounds, and the low fat group lost an average of 5 pounds — not a whole lot considering most of the subjects were 60 pounds overweight. Both diets lowered blood pressure and insulin response to an oral glucose test. The low carb group had a greater reduction in their triglycerides than the low-fat group. [Triglycerides are one measure of fats carried in the bloodstream, and are influenced by simple carbohydrate (i.e., sugars) intake and other factors.] Other researchers' work showed slightly more weight lost on low carb vs. low-fat diets, but most of these studies were shorter in duration, lasting only six months.

The short-term study of weight loss diets cannot reveal their safety over the long run. Some health considerations include the following:

• It's not known whether eating large amounts of saturated fat (as in the Atkins's diet) will later increase cholesterol levels, or cause a greater incidence of prostate or other cancers.
• Although cholesterol levels may decrease in the short run, it's unknown if high saturated fat intake influences our arteries' ability to collect cholesterol deposits over time.
• It's unclear whether or not high protein diets jeopardize bone health, since excess consumption of animal protein causes excretion of calcium in urine.
• It is known that a lack of carbohydrates makes it difficult to exercise — especially in higher intensity or longer duration aerobic activities. These activities are beneficial in preventing and treating heart disease, hypertension, diabetes, arthritis, and some forms of cancer, and in weight and stress management.
• It's uncertain if high protein diets cause kidney damage. Common sense tells us that the kidneys work harder to excrete excess fluid lost on a high protein diet, but it's not known yet if this translates into disease. What about people who are in the early stages of kidney disease and don't know it? Perhaps a high protein diet may in fact be harmful to them.

Dr. Foster is planning a new study to investigate many of these issues, with more people, over a longer period of time.

Gastrointestinal disorders may be worsened by a high fat, low fiber intake. Constipation, GERD (gastroesophageal, or acid, reflux), irritable bowel syndrome, and diverticulosis are a few that come to mind. High protein diets often lack a variety of fruits, vegetables, and whole grains that contain a multitude of beneficial substances, such as fiber, vitamins, minerals, antioxidants, and other naturally occurring plant chemicals (phytochemicals). Thousands of studies have proven these substances as healthful. Eating just one green salad a day cannot provide all of the nutrients excluded in the Atkins diet.

Since there are so many unanswered questions about the long-term health effects of the low carb, Atkins's style diet, a variety of nutritious foods is preferred as a sound, long-term strategy instead. What is important in the long run is not what the scale shows after a few short months, but whether your risk for heart disease, stroke, diabetes, and cancer is low, and that you are healthy, active, and satisfied with your food choices.

Alice

Related Q&As

Why are whole grains healthier?

Heart Foundation diet?

Confused about carbs: What's a good carbohydrate choice?

Does carbohydrate become body fat?