This analysis of NHANES 2003–2006 data using the food disaggregation approach shows that some of the major sources of calories, added sugars, and SFA in the US diet are also major sources of dietary essential nutrients including nutrients that are underconsumed. That said, three of the top 10 sources of calories, including ‘soft drinks, soda,’ ‘candy, sugars, and sugary foods,’ and ‘alcoholic beverages’ contribute calories but have virtually no nutritional value, while the other calorie sources, including beef, poultry, milk, cheese, and baked goods are major sources of nutrients of concern and other essential nutrients. The top five sources of added sugars account for 83% of the population’s added sugar intake but with few exceptions, they provide little or no nutritional value. In contrast, the top three sources of SFA (cheese, beef, and milk) contribute more than 40% of the vitamin B12, almost half of the vitamin D and calcium, and are major sources of other essential nutrients to the American diet.
The DGA’s “as consumed” listings of top sources of calories, added sugar, and SFA tell us what foods Americans are putting on their plates that are contributing to high intake of these food components . This information is useful to help consumers identify healthier forms of these foods or to avoid foods with little or no nutritional value. But, in the case of foods that can be eaten by themselves or as a part of mixed dishes, information from a disaggregated approach gives insight into an individual food’s relative contribution to intakes of added sugars and/or SFA as well as essential nutrients to the American diet. For example, compared to DGA rankings, the contribution of beef to SFA intake is actually emphasized by the disaggregated approach as is its importance to the population’s zinc (20.1%) and vitamin B12 intake (18.6%). This additional insight can help enable informed choices; e.g., choosing leaner beef rather than eliminating beef from the diet with associated reductions in intakes of certain essential nutrients.
Reduction of total calorie intake for weight loss requires a broad and balanced approach because no one food category makes a large impact on total calories. The food categories with the largest contribution to calorie intake as listed in the DGA are grain-based desserts (6.4% of the total caloric intake) and in the present analyses are ‘cakes, cookies, quick bread, pastry, pie’ (7.2%). But, the present analysis reveals also that three categories (‘soft drinks, soda,’ ‘candy, sugars and sugary foods,’ and ‘alcoholic beverages’) contribute 13.6% of total calorie intake (296 kcal/day) and provide little to no other nutritional value. Reducing intake of these foods could greatly reduce population caloric intake without compromising the overall nutritional quality of the diet.
The predominance of foods providing empty calories is readily apparent in the added sugars analysis. Given the disaggregated food approach in the present study, slightly higher estimates of empty calories are provided by the top five sources of added sugar (83.3%) when compared to the foods listed in the DGA, which are based on the foods as consumed approach (71.7%). The most notable nutrient-dense food in this list, ready-to-eat cereals, contributes only 3.9% of the total added sugar intake while providing 6-22% of 11 different vitamins and minerals to the diet of Americans. Recommending healthier ready-to-eat cereals may be an effective means of increasing intakes of nutrients of concern like fiber, but may lead to only modest reductions to the overall intake of added sugars.
In sharp contrast to the added sugars results, while the top three sources of SFA (cheese, beef, and milk) provide a third of dietary SFA, they also contribute 49.5% of vitamin D, 46.3% of calcium, 42.3% of vitamin B12 and 11.6% of the potassium as well as a host of other nutrients to the diet of Americans. The DGA recommends consuming less than 10% of calories from SFA, which is about a 15% reduction from the current 11.4% of calories. This recommendation is based primarily on the role of SFA in increasing LDL cholesterol, which is linked to increased risk for cardiovascular disease [23, 24]. However, not all food sources of SFA are the same. Different fatty acid chain lengths have different biological effects, and other non-fatty acid nutrients contained within specific foods also play a role in modifying disease risk (3). Replacing SFA with PUFA, for example, significantly reduces cardiovascular disease risk, whereas the evidence for replacing SFA with carbohydrate or MUFA is less consistent and robust, suggesting that lowering risk may be more strongly related to increased intakes of PUFA rather than decreased SFA [25–27]. Evidence that substituting the omega-6 PUFA, linoleic acid, for SFA may not be beneficial points to the potential for differential effects of specific PUFA . Furthermore, reliance on the level of a single lipid nutrient (SFA) in a food and a single plasma biomarker (LDL-C) may not adequately characterize the cardiovascular impact of complex foods that contain, in addition to SFA, multiple nutrients and other bioactive components that reduce CVD risk. For example, intake of milk and milk products is associated with a reduced risk for CVD despite being a major contributor to SFA intake . Thus, other components in milk and milk products, such as calcium, potassium, magnesium, protein (whey, casein), and vitamins D and B12 may confer favorable cardiovascular effects [29–33].
The 2010 Dietary Guidelines Advisory Committee (DGAC) report through its evidence based review concluded that not all SFA have the same effect on disease risk, noting that fat from dairy products is an area that requires further study . The report indicated that consumption of milk products may not have predictable effects on blood lipids and future research should examine the role of dairy products in modulating lipid profiles, noting that bioactive components that alter serum lipid levels may be contained in milk fat. The report also states that evidence to date does not suggest that high-fat dairy products are more likely than low-fat dairy products to induce metabolic syndrome.
More frequent consumption of dairy products, vegetables, fruits, and whole grains is recommended to increase intakes of potassium, dietary fiber, calcium, and vitamin D . The DGA recommends preferentially choosing lean meat and poultry and low-fat and fat-free dairy products, including milk, cheese and yogurt, over higher fat forms to help balance calorie intakes. The widespread availability of low-fat and fat-free milks, however, has not offset the overall decline in milk consumption since 1980 (−21%) and the even larger decline in whole milk consumption alone (−65%) . An Australian study of the dietary consequences of recommending lower-fat dairy foods to overweight adults found men decreased their overall intake of dairy foods significantly, rather than switch to lower fat versions . It is not well understood what role the amount of milk fat plays in maintaining or increasing milk consumption among those with a preference for higher fat milk and encouraging milk consumption among those who infrequently consume milk products.
While the DGA recommends mainly choosing lower-fat cheeses, achieving flavor, texture, color, and other attributes comparable to full-fat versions is challenging for cheese manufacturers, particularly at the greater than 50% reductions in fat [37–41] needed to label cheese as low-fat or fat-free. Low-fat cheddar, for example, must contain 80% less fat than its full-fat counterpart to meet federal labeling requirements. Consumers are discerning and acceptance of lower-fat cheeses can be poor, even when differences are small. Consumer acceptance of reduced-fat cheese, which requires a 25% reduction in fat, has seen greater success than low-fat and fat-free forms of cheese [42, 43].