The higher one's education level, the greater the preference for low-calorie diets which are rich in nutrients, but cost more.
University of Washington (UW) researchers compared eating habits and food costs of a sample of 164 adults in the Washington area.
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 such as sweets, candy and desserts.
Diets of low energy density and high nutrient content have been associated with less weight gain and with lower rates of obesity, cardiovascular disease and some forms of cancer.
The 164 participants (103 women and 61 men) recorded their usual frequency of consumption of 152 foods and 22 beverages and indicated portion size. They also provided four-day dietary records and completed demographic and behavioural questionnaires.
For both men and women, higher dietary energy density was associated with higher intakes of total fat and saturated fat and with lower intakes of dietary fibre, potassium and vitamins A and C.
For each 2,000 calories of dietary energy, men spent $7.43 compared to $8.12 spent by women. Diets that were more costly in terms of dollars per 2,000 calories were also lower in energy density and contained higher levels of nutrients.
Higher quality diets were not only more costly per 2,000 calories but were associated with higher household incomes and education of study participants, said an UW release.
Education, rather than income was the dominant factor. More highly educated respondents reported higher quality and therefore more costly diets, independent of household income levels.
These findings were published in the May issue of the Journal of the American Dietetic Association.