March 7, 2007 — -- A study in the Journal of the American Medical Association adds more information to the long-running debate about what kind of diet is best for weight loss.
Several recent studies suggest that overweight people might have more success with weight loss when they follow a diet lower in carbohydrates (and higher in fat and protein) than by following the standard guidelines for a lower fat, higher carbohydrate diet.
These findings have surprised and concerned many nutritional experts. Critics have correctly pointed out that these studies didn't involve enough people and were too short in duration to draw strong conclusions or to change standard recommendations.
This new study followed patients for one year -- longer than many of the previous studies.
Approximately 300 overweight or obese women were put on one of four diets: the Atkins diet -- very low in carbohydrates; the Zone diet -- moderately low in carbohydrates; a diet based on current national guidelines for a moderately low fat, high carbohydrate plan; and the very low fat Ornish diet.
At the end of one year, those following the Atkins diet lost the most weight, approximately 10 pounds.
Those on the other plans lost on average 3.5 to six pounds.
The researchers also measured other factors that are known to affect heart disease risk, including blood pressure, levels of cholesterol and blood fats known as triglycerides.
Of all the plans, the Atkins diet had the most favorable effects on the good cholesterol, triglycerides and blood pressure. Levels of bad cholesterol did not differ significantly among the groups during most of the study.
While this study appears to have been well conducted, like all research, it needs to be interpreted with care.
The research involved only women between the ages of 25 and 50. It did not include men, children or seniors. That may make a difference.
The concern about the longer term still remains: What happens as people drift off their specific diet? While those following Atkins had indeed lost more weight, at the end of one year, the gap between the diets was narrowing.
I have to wonder whether women who had not been taught to limit their calories, as is true on the Atkins plan, might have even more difficulty reining in their weight as they returned to a less restrictive pattern of eating.
Finally, this study was not designed to address all the potential health implications of the diets studied.
How might they affect people who are not trying to lose weight? How about those who have already lost and are trying to keep their weight stable?
I remain concerned about the higher intake of saturated fat and lower levels of fiber in low carb plans and how this may affect true risk for heart disease or cancer. Favorable changes in cholesterol and triglycerides in those on a lower carb, higher fat diet may hint at long-term benefit, but are not the same as being able to measure actual heart health outcomes like heart attacks.
If you're confused and frustrated by the inconsistent and often conflicting research findings about weight loss that are seemingly published and reported every week, I can sympathize with you.
Sometimes it's even difficult for me as an obesity treatment expert to make sense of it all. It is incredibly difficult to design and conduct the kind of large-scale, well-controlled nutritional studies that might provide us with the most definitive answers.
But a great deal of good research HAS been done, and it has become clear that solving the obesity problem will NOT be about the specific diet.
Most experts agree that, more important than specific diet composition, are the following recommendations -- not only for weight control, but for overall health:
And both for weight loss AND overall health, add regular physical activity to your day -- aim for 40 minutes to an hour daily.
Unfortunately, there is no easy way to lose weight. It's about making good choices every day. Remember the proverb that concludes by saying, "Slow and steady wins the race"? That's especially true in dieting and weight loss, and I know you can do it if you put your mind to it.
Dr. Howard Eisenson is director of the Duke Diet and Fitness Center at Duke University in Durham, N.C.