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COMMENTARY |
Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland, E-mail: david.klurfeld{at}nps.ars.usda.gov
In a commentary in this issue of JACN, Anderson and Patterson [1] suggest that children should eat fruits, vegetables and low fat dairy for snacks while avoiding typical snack foods such as candy, chips, cookies and so forth. They suggest that the government should identify "good" and "bad" snacks and create economic conditions to promote those choices. Although the basic premise that choice of snacks will affect both macronutrient and total energy intake is sound, the suggestions that follow are based on emotional appeal rather than on evidence. The authors of the commentary ignore the view that snacks, by definition, should represent only a minor portion of daily energy intake. Small portions of energy-dense, nutrient-poor foods can be added to a sound diet without harm if energy balance is maintained. The authors also ignore that fact that energy intake among children has not increased between 1971 and 2000 even though obesity has [2]. In fact, longitudinal data from the Bogalusa Heart Study shows that children were eating dessert and candy less in 1994 than in 1974 but more beverages, snacks of all types including fruit (excluding candy) and larger portion sizes of most foods [3]. Recent data from a prospective study of 15,000 children indicates that snack food intake does not predict weight change [4].
A basically sound diet that meets nutrient requirements has room for discretionary calories designated by the 2005 Dietary Guidelines for Americans Advisory Committee as representing calories above those needed from foods that provide essential nutrient requirements [5]. For most people those discretionary calories are approximately 100 to 200 kcal/day. It is probably irrelevant if those extra calories are provided by extra servings of nutrient dense foods or low-nutrient foods. A diet that is not well constructed will not benefit much from healthy snacks. One could make the same observations as the authors have for snack foods and conclude that eating in restaurants should be banned, or at least taxed at a level to discourage it, since eating away from home correlates strongly with increased body weight, higher fat, sugar and sodium intake. While there is a certain puritanical appeal of taxing candy bars, paying 20–30 percent or more extra for a meal in a restaurant is certainly not a position that would garner widespread support from scientists or the public. Adequate physical activity is required to have a flexible calorie allowance and too many Americans, children included, do not expend enough energy in physical activity due to societal changes in lifestyle, recreation, and employment.
The authors also ignore the lack of evidence for the changes they suggest. Economic disincentives, i.e., taxes, do not have much impact on alcohol or tobacco consumption in this country; public health education and social mores interact with the increased taxes on these items so determining a cause and effect relationship is not possible. Both tobacco and alcohol are special cases, as well. Tobacco is the only consumer product that is unhealthy when used as intended. Alcohol is beneficial when consumed in light to moderate amounts but has the potential for abuse with concomitant social and health problems. In fact, virtually everyone who smokes or consumes excess alcohol knows these are unhealthy so education is also not a panacea. When food continues to cost a smaller and smaller percentage of our income, only a punitively high tax might have an effect but there are no data to support a major effect on consumption. Such a tax would have a disproportionate impact on people in lower socioeconomic strata and the wealthy would continue their eating habits. In addition, studies have shown repeatedly that when children are told they should not consume particular foods, those foods become more desirable to the children, having an effect opposite of that intended [6].
It is curious that Anderson and Patterson cite popcorn and trail mix as undesirable snacks. Popcorn is the only whole grain snack there is and can vary from 89 to 154 kcal/ounce, but a serving of popcorn can be less than an ounce [7]. Trail mix is generally composed of dried fruits and nuts. Fruits are already recommended by the authors and it is not likely they would argue that nuts are unhealthy. The Food and Drug Administration has acknowledged health-promoting aspects of nut consumption by authorization of a limited health claim based upon both epidemiological and experimental evidence [8]. Many other ingredients such as seeds, dried coconut or chocolate may be added but there is no standard of identity for trail mix. These examples indicate it is possible to choose healthy snacks from within a category labeled as "junk." It is surprising that Anderson and Patterson do not mention consumption of sweetened beverages (primarily soft drinks and fruit drinks), which account for a larger percentage of daily calories and provide fewer nutrients than any of the snack foods they cite.
There is no argument that fruits, vegetables and low fat dairy are excellent snacks. But good intentions are not a substitute for evidence, which is noticeably lacking in this discussion that has been promoted by some scientists and consumer activists. We should remain cognizant of the fact that telling people what they can or cannot eat via education or economic disincentives may very well not have the desired effect. The enthusiasm to ban vending machines from schools is high yet the state of West Virginia banned vending machines in schools in 1975 and has one of the highest rates of obesity in the nation. Fruits are the stereotypical snack foods, being tasty, portable, often in single serving sizes and are not costly yet consumption has not risen and according to some surveys has trended downward in recent years. At the same time, obesity has increased in the U.S. and in most other countries where eating and snacking patterns differ considerably. There is universal agreement that obesity is multifactorial in nature. It should be acknowledged that complex behavioral choices associated with eating and physical activity contribute to this problem, parental habits play a role for children, objective data on efficacy of potential solutions are needed and coercion from the government is not likely to solve the problem.
FOOTNOTES
* The views expressed here are the personal views of the author and do not necessarily represent those of the U.S. Department of Agriculture. 
References
dms/qhcnuts2.ht.
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