You eat what you are.
The energy density of the diet (i.e. available energy per unit weight) is one indicator of diet quality. Lean meats, fish, low-fat dairy products and fresh vegetables and fruit provide fewer calories per unit weight than do fast foods, sweets, candy and desserts. Energy dense foods provide more calories per unit weight but tend to be nutrient-poor.
Diets of low energy density and high nutrient content have been associated with less weight gain and with lower rates of obesity, type 2 diabetes, cardiovascular disease and some forms of cancer. In contrast, energy-dense diets have been linked to higher obesity rates and higher disease risk. Improving diet quality by lowering its energy density is standard advice for weight control, cancer prevention and better health.
The finding that higher-quality diets were consumed by women of higher socioeconomic status and more costly per 2000 kcal has implications for epidemiologic studies of diet and chronic disease. Nutritional epidemiology has historically been based on the premise that nutrient exposures are directly linked to health outcomes. However, nutritional status is also intimately linked to socioeconomic status, and the findings reported here raise the possibility that the higher monetary cost of nutritious diets may provide one explanation for these observations. Future studies, based on more representative samples, will be needed to elucidate the connections between diet quality and diet cost across socioeconomic strata." Eat Up!