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LETTER TO THE EDITOR |
Carolina Population Center
University of North Carolina
123 West Franklin Street
Chapel Hill, NC 27516
E-mail: popkin{at}unc.edu
University of Connecticut
Human Performance Laboratory
Storrs, CT
Louisiana State University Medical Center
Pennington Biomedical Research Center
Baton Rouge, LA
Johns Hopkins University
Baltimore, MD
Linus Pauling Institute
Oregon State University
Corvallis, OR
Harvard School of Public Health
Boston, MA
Dear Sir:
It is useful to have Kaplan, an employee of the Canadian Sugar Institute, raise publicly his concerns about research on this topic. The "beverage guidance system" proposed by our group of scholars was developed to address a major deficiency in the dietary advice for Americans—the lack of clear guidance on the use of beverages in our diet (1). One factor in our ranking was that calories from beverages lead more easily to an excess in total caloric intake because there is inadequate compensation for these calories by a reduction of intake of other foods (2-4). The letter by Kaplan does not adequately address this central issue, but rather attempts to diminish the proposed beverage guidance system with counterfacts and a range of arguments that do not address the points raised by our article.
Kaplan bases his critique on 2 frequently recycled arguments: 1) that there are no good or bad foods, and 2) that there is no evidence of an increase in the consumption of sweetened drinks in the United States nor of a causal link to obesity.
Assertion: there are no good foods or bad foods
Many segments of the food industry, in particular companies that produce candy; high fat, salty snacks; and poor quality foods, have argued that we must never condemn individual food items but rather should discuss overall diets. Actually, since the discovery of essential nutrients 100 y ago, foods have been qualified and ranked based on their content of those essential components. Although one must try to avoid judgmental terms such as "good" or "bad" when giving dietary advice, our panel believes that some foods are beneficial for health and others are detrimental. True, an unhealthy food consumed infrequently and in small amounts may do no harm, but this is simply a function of exposure and is also valid for many toxic substances. Furthermore, our article addresses specifically the current US situation, which is characterized by excessive dietary energy intake and marginal consumption of several essential nutrients. In this context, caloric beverages are of legitimate concern because sweetened beverages are responsible for almost half the increase in energy intake seen over the past decade (5) and because they displace other caloric sources that are nutrient rich (6). This does not make sweetened beverages "bad," but certainly makes them less healthy for our current situation.
Assertion: the Beverage Guidance Panel is misguided when using nutrient content to rank foods. Foods and beverages should not be ranked
As noted above, ranking foods and beverages is a basic aspect of all dietary guidelines around the world. Our panel was constituted on the premises that beverages as a total category had been relatively ignored and that dietary guidelines ignored beverages except for fluids such as milk and juice. If we are to improve dietary patterns, it is essential for scientists to provide consumption guidelines regarding the components of food and beverages, be they water, whole grains, fruit, or vegetables.
Assertion: sweetened beverage intake has declined
The argument that there is no evidence of an increase in sweetened beverage intake or its causal link to obesity is also flawed. "Per capita" consumption and disappearance data are useful for macroeconomic analyses of trends in production or marketing, but they do not represent actual intake by individuals. In particular, the dietary intake surveys of adolescents and young adults indicate a substantial increase in caloric soft drink intake (5, 7).
Our panel was concerned with intake of all caloric beverages (ie, including soft drinks, fruit punches, and fruit juice). Moreover, we focused on the health benefits of each beverage group. If food disappearance data were verified by dietary intake data, this would be excellent but would not address our concerns. However, it is clear from our research, as well as that published by others, that soft drink and other sweetened beverage intakes continue to increase and that food disappearance data do not represent individual dietary trends (5, 8)
The Beverage Guidance Panel did not use ecologic analysis as part of its analysis of the relation between calorically sweetened beverage and obesity. Rather, we just noted that the increase in caloric intake from beverages was very large and played a major role in the epidemic of obesity. The fact that the average American adult consumes 
500 kcal/d from beverages, which represents >21% of their average daily energy intake, is disconcerting. Furthermore, this represents a very large increase in calorie intake from beverages over the past several decades.
Regarding the link with obesity, we agree that no randomized controlled trials have shown that consumption of sweetened beverages causes obesity. That kind of trial is logistically unfeasible at this point. But we do know that sweetened beverages have contributed disproportionately to the rise in daily energy consumption in the United States. We also know that removing sweetened beverages from the diet results in significant weight loss in overweight persons (9-11). These findings are not trivial, when 2 of every 3 adults in the United States are overweight. Thus, although we cannot claim that sweetened beverages cause obesity, we feel our recommendation to minimize their consumption is clearly supported by published evidence and inference.
Assertion: the panel selectively reviewed the evidence
Our Beverage Guidance system cited high-quality studies that address the issues we raised. Kaplan notes that we did not include a recent review published in April of this year (12). That article was published after publication of our article. Although true, we also did not include many other new articles that reported relations between the consumption of soft drinks and future weight gain (9, 10, 13).
In a second issue related to sweet preferences, our panel felt that the evidence of the role of noncaloric sweetened beverages in body weight change was adequate, and we recommended caution regarding the excessive use of such beverages.
Assertion: there is no evidence to recommend an ideal beverage pattern
We agree with Kaplan that beverage needs for each person are highly variable and based on age, sex, and a range of physiologic variables. We carefully noted this in our article and stated that there are many ways to meet beverage needs; these included consuming only water, water plus unsweetened tea and coffee, and many other beverage combinations. We are concerned that American adults, older children, and adolescents are consuming too many calories from beverages and that the number of beverage calories should be reduced.
The use of beverages in our article had a basis on sample menus published by the Institute of Medicine Dietary Reference Intakes report on water and electrolytes (14). We used these examples because they fulfill the requirements for all nutrients for which there is a Recommended Dietary Allowance (or Adequate Intakes), and fulfill the requirements for energy and water. Although many other combinations of foods are certainly possible, the principle of limiting the amount of calories derived from beverages still applies.
In conclusion, our Beverage Guidance Panel feels we have responded to each assertion to show that there are meaningful scientific arguments to support our study and our recommendations.
ACKNOWLEDGMENTS
The authors had no conflicts of interest.
REFERENCES
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