Most summary systems include negative nutrients, and the evidence for effects on health is more clearly known than for negative than for positive nutrients.
The 2010 DGA recommends that saturated fat intake be less than 10% of recommended energy intake as an interim goal, with an ultimate goal of <7%. The 2005 DGA had a goal of less than 10% of energy from saturated fat, which is 20 g based on a 2,000 kcal/day reference diet. Saturated fat is associated with increased low-density lipoprotein (LDL), and high serum LDL concentrations are associated with increased risk of CVD (Mensick, Zock, Kester, & Katan, 2003). Intake of trans fat should be "minimal" or "as low as possible" as recommended by the 2010 and 2005 DGA, respectively. Trans fat adversely lowers high density lipoprotein (HDL) cholesterol (Mensick et al., 2003) and has similar effects on LDL and CVD as saturated fats (Mozaffarian, Katan, Ascherio, Stampfer, & Willett, 2006). The 2010 and 2005 DGA recommend limiting cholesterol to 300 mg/d. Cholesterol is associated with increased risk of CVD, but changes in dietary cholesterol have only modest effects on plasma cholesterol concentrations (Connor & Connor, 2002). FDA has evaluated the scientific evidence for saturated fat and cholesterol and risk of CHD and issued health claim regulation regarding saturated fat and cholesterol and risk of CHD (Code of Federal Regulations, 1993b). Total fat includes both "bad" fats (saturated and trans fatty acids) and "good" fats, (polyunsaturated and monounsaturated fatty acids). The 2005 DGA recommends intake of total fat to be between 20% and 35% of calories for adults, but the 2010 DGA do not recommend a specific limit to total fat intake. Although the evidence for the effect of total fat on disease risk is not supported by science, a high intake of total fat generally increases saturated fat and energy intakes. The percentage of energy intake from fat is not associated with obesity (Willett, 2002). The 2010 DGA recommend replacing saturated fats with monounsaturated and polyunsaturated fatty acids in an effort to reduce intake of saturated fats to less than 10% of calories.
Sugar has long been known to cause dental caries, but recent data have implicated sugar, primarily from high intake of sweetened beverages, in obesity (Malik, Schulze, & Hu, 2006). Associations between sugar intake and obesity do not imply causality and are confounded by the fact that sugar is a source of energy. The 2010 DGA does not set a specific guideline for sugar intake; however, it states that Americans consume too many calories from solid fats and added sugars (SoFAS), and intake should be reduced to no more than 5 to 15% of total calories from SoFAS. The Institute of Medicine recommendation for added sugar intake is no more than 25% of total energy, or 125 g for a 2,000 kcal/d diet (Food and Nutrition Board. Institute of Medicine, 2002). The WHO recommends limiting daily intake of "free" sugar to no more than 10% of total energy (WHO, 2003).
Excess sodium intake is associated with elevated blood pressure (Obarzanek et al., 2003), and salt restriction lowers blood pressure (Law, Frost, & Wald, 1991). FDA reviewed the evidence and issued health claim regulation for sodium and hypertension (Code of Federal Regulations, 1993a). Elevated blood pressure is a risk factor for CHD and stroke. The 2005 and 2010 DGA recommend a sodium intake of 2,300 mg/d, but an ultimate goal of 1,500 mg/d is recommended by the 2010 DGA.