Nutrition Expert Discusses New Dietary Guidelines

The Department of Health and Human Services (HHS) and the Department of Agriculture (USDA) released the official 2005 Dietary Guidelines for Americans on January 12. The guidelines, which are updated every 5 years, are intended to help individuals choose diets that will promote optimal health and reduce risk of chronic disease. They are an indispensable tool to guide all government nutrition programs, including research, education, food assistance, labeling, and nutrition promotion.

The updated guidelines were based on the report of the 13-member Dietary Guidelines Advisory Committee (DGAC) issued in August 2004. Benjamin Caballero, PhD, MD, director of the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health, and Lawrence Appel, MD, professor with the Bloomberg School’s Department of International Health, served on that scientific panel. Caballero also sat on the Institute of Medicine committee that wrote the Dietary Reference Intakes for Macronutrients, published in 2002. 

Kelly Blake, communications and publications coordinator for the Center for Human Nutrition, spoke with Dr. Caballero about the final report. 

Kelly Blake: Some have criticized the fact that the final report did not specify a limit for trans fat, while the DGAC report capped trans fat intake at 1 percent of total calories. Do you see this as a problem?

Benjamin Caballero: Since there is no physiological requirement for trans fats and the adverse effects are known, an ideal diet should contain zero. However, even if the food industry eliminates trans fats completely from their products, a typical healthy, diet may realistically still contain about 0.4 percent of calories from trans fats from naturally-occuring sources, like animal products. Based on this, some countries have set a maximum of 1 percent, which is what we [DGAG] recommended. The government, who has the responsibility of translating these recommendations into regulations, felt that the difference between “maximum” and “allowed” is often lost in practice, and that setting a level would result in our diet having 0.99 percent of calories from trans forever, instead of continuing to push toward zero. So, I think the statement “as low as possible” better reflects the fact that there is no acceptable level for trans fats. Consumers can actually use this to hold the food industry accountable by demanding products with the lowest possible trans content, not just 1 percent.

KB: What about the recommendation to “choose and prepare foods with little added sugars?”  This is a more explicit statement about sugar than was included in the DGAC report.  How do you feel about the change?

BC: While we did not include this statement in the 9 “key points” we outlined, it was actually included in the explanatory text that followed. Our report concluded that there is evidence that increasing consumption of sugars increases total energy intake, and that the limited evidence available suggests that sugars may result in excess weight gain. The data presented in the final guideline is also taken directly from our report.

KB: The new guidelines also recommend a minimum of 30 minutes of daily exercise and suggest that 60 minutes a day is needed to maintain body weight, and as much as 90 minutes to lose weight.  The DGAC report only specified 30 minutes on most days. The 30-90 minutes is more in line with the Institute of Medicine’s recommendation in the Dietary Reference Intakes. Are you satisfied with that change?

BC: Again, the final guideline is totally consistent with our report. We recommended a minimum of 30 minutes for everyone, and said that “most people” will need 60 minutes to avoid weight gain. There is increasing recognition that for a sedentary person, as little as 20 minutes of moderate activity per day can offer a significant reduction in risk for chronic diseases. There is a dose-response, in other words, you gain additional benefits for longer periods of activity. 

Weight maintenance is another matter. According to the IOM report, most people will require 60 minutes to avoid weight gain.  Finally, the 90 minute recommendation is for formerly obese persons who lost weight.  For reasons that are not completely clear, people who were obese and lost weight require more physical activity to avoid weight regain than persons who were never obese. No specific level of physical activity for weight loss has been set because this has to be individualized according to the calorie deficit of the weight loss diet and the other components of the weight loss program.  However, it is recommended that physical activity be part of all weight loss programs (since these people will have to do 90 minutes per day after they successfully lose the weight to keep it off, their chances of success are much greater if they incorporate it into their daily routine as soon as possible.)

KB: During the January 12th press conference, HHS Secretary Tommy Thompson answered a question about whether food cost might be a factor in determining whether low-income Americans will be able to adhere to the Dietary Guidelines by saying he did not think cost was a determining factor.  Do you believe that cost or other factors hinder people from following the recommended guidelines?  

BC: I think cost and access to fresh fruits and vegetables are indeed factors we need to consider.  Unhealthy foods are readily available (you don’t even have to step out of the car!) and very cheap on a per-calorie basis. Making healthy foods as easy to get and afford will certainly make it much easier for people to follow these guidelines.--Kelly Blake 

Related links:
The Dietary Guidelines for Americans 2005 Report

The complete 2005 Dietary Guidelines Advisory Committee Report

 Web article about the development of the Dietary Guidelines Advisory Committee Report 

 Dietary Guidelines Advisory Committee 2005 Report