Low-Carb Vs. Low-Fat Diets

New research suggests that in the short term, a low carbohydrate diet may be more effective, and in some ways healthier, than traditional low-fat diets.

But, The Early Show medical correspondent Dr. Emily Senay explains, some question the low-carb diet's long-term effectiveness.

Many, including Dr. Robert Atkins, who died just over a month ago, have promoted the idea of restricting carbohydrates instead of fat to lose weight. But, Dr. Senay says, not everybody is convinced it's a good idea.

For now, two new studies in the New England Journal of Medicine provides evidence that in the short term, a low-carb diet helped people lose weight without any adverse effects, and improved some indicators of health.

One study followed severely obese people with a high rate of diabetes and high risk for heart disease for six months. They found those people lost more weight on a low-carb diet -- an average of almost 13 pounds compared to the low-fat diet, where people lost an average of about four pounds.

The low-carb group also had improvements in insulin sensitivity and lower triglyceride levels, an important risk factor for heart disease.

The second study found at six months that those on a low-carb diet lost more weight than those on the low fat diet — an average of about 15 pounds compared to seven pounds. There was also an increase in good cholesterol or HDL, and lower triglyceride levels.

Dr. Senay says in both studies, bad cholesterol (LDL cholesterol) and blood pressure were not significantly raised. But, by the end of the year, a lot of weight had been regained -- so that the difference in weight loss between the diets was not significant.

Although the studies show a low-carb diet does result in weight loss in the short term and has some short-term health benefits, the verdict on the diet's long-term benefits is still debatable, says Dr. Senay.

The numbers of participants in both studies was relatively small, and the researchers did not follow up with the participants to see what the longer-term weight loss and health effects were.

Dr. Senay says the problem with the most weight loss programs is that people tend to put the weight back on over time.