Eat more vegetables. Cut down on fat intake. We all know we should, but what makes someone actually do it?
Scientists in the Public Health Sciences Division and the University of Washington think they have some answers.
In a study published in the this month's Journal of the American Dietetic Association, Dr. Alan Kristal and colleagues found that those most likely to make significant healthy changes to their diet include women, highly educated people and those who believe that there is a strong relationship between diet and cancer.
"The study confirms that some of the demographic characteristics - such as being female, older or better educated - that are associated with eating healthier diets also predict healthful changes," Kristal said.
The research was motivated in part by the observation that individuals in control groups of dietary intervention studies often improve their diets, but the factors responsible for this self-initiated change were unknown.
The study monitored dietary habits as well as attitudes and behaviors related to cancer risk and prevention of more than 800 men and women in Washington state. Participant information was collected in 1995 and 1996 to establish a baseline and two years later to evaluate any changes.
"What is new about this work is that almost all other studies of predictors of healthful diets are cross-sectional - a snapshot of one point in time," Kristal said. "Studies of that nature make it impossible to say what predicts change."
In addition to women, older and highly educated individuals, those who read food labels made significant changes reductions in fat consumption.
The investigators also evaluated whether preexisting healthy eating habits influence further change, using a popular health-behavior model known as the Transtheoretical Model.
This model would predict that people who reported having made extensive behavior changes and maintained them for at least a year would not be likely to make further changes in eating habits. However, the Hutch study found that these people made the greatest changes.
"One point my group has been making for years is that this health-behavior model, developed around smoking cessation and drug abstinence, must be carefully reinterpreted when applied to diet," Kristal said.