A diet high in fruit and vegetables and low in fat is hypothesized to improve breast cancer prognosis and decrease risk of recurrence. Armed with the knowledge that women with breast cancer are highly motivated to make lifestyle changes, and that women with cancer-prevention knowledge are more likely to make changes in their diet, several intervention trials have been established with the goal of helping women with breast cancer make healthful dietary changes. Many women appear to be aware of this dietary advice, as several recent nonintervention studies have found that breast cancer survivors report they have increased their intake of fruits and vegetables while decreasing their fat intake. The present study had two aims. First, the researchers intended to quantify changes in dietary intake after breast cancer diagnosis using data from a food frequency questionnaire administered at two points in time. Intake of kilocalories, macronutrients, and fruit and vegetable servings 1 year before breast cancer diagnosis was compared with intake l-year postdiagnosis and relevant demographic and treatment factors were evaluated. Second, comparisons were made between self-reported change in fruit, vegetable, and fat intake and change in intake of these items as measured by repeated food frequency questionnaires.

The subjects included 260 New Mexico women, part of a larger, population-based, prospective cohort study of breast cancer prognosis called the Health, Eating, Activity, and Lifestyle study. This study enrolled women with newly diagnosed breast cancer between August 1996 and March 1999. A short dietary screener was collected on all women, and a food frequency questionnaire Was added part of the way through the study as additional funding made this possible.
Two-year change scores for kilocalories, macronutrients, and fruit and vegetable servings were calculated and tested for difference from zero. Amount of change in fruit and vegetable servings and fat intake were calculated using food frequency data from women who reported increasing their intake of fruits and vegetables or decreasing their intake of fat after diagnosis.

Small but significant decreases in intake of total energy and macronutrients were found 2 years postdiagnosis, with younger women reporting the greatest decreases. Fat as a percentage of diet increased over this period. There was no change in mean intake of fruit and vegetable servings. There is agreement between change as measured by food frequency questionnaire and change reported by more global questions on dietary habits; however, the amount of change measured was small. Women reporting an increase in fruit and vegetable intake post-diagnosis described an increase of one-quarter serving of fruit and one-third serving of vegetables per day.

In conclusion, breast cancer diagnosis results in modest dietary changes. Small changes in fruit and vegetable consumption suggest that efforts are needed to encourage increased consumption of these foods. Women who report increasing fruit and vegetable servings after breast cancer diagnosis report intakes that are, on average, still below the recommended five servings per day. For this reason, dietary intervention efforts should be targeted toward all women, not merely those who report no increase in fruit and vegetable consumption.