ABSTRACT
With improving economy and abundant food supply, excess food intake has been strongly linked to the increasing epidemic proportion of overweight or obesity in the United States in recent decades. Obesity is an important risk factor contributing toward the development of leading causes of death, such as cardiovascular disease, cancer, and diabetes, in the United States (Engelhart et al., 2002; Ernst et al., 1997; Hu et al., 2000; U.S. Department of Health and Human Services, 2001). The medical expenses and lost productivity resulting from these diet-related diseases are already very high, and are continuously increasing at a rapid rate (Hef, er et al., 2002; Westerhout, 2006).
