Fruits, Vegetables, and Whole Grains: A Community-based Intervention

Governments and major national agencies throughout the western world concerned with chronic disease prevention (heart disease, stroke, diabetes, and cancer) uniformly advocate increased intakes of fruit, vegetables and whole grain cereals. All also agree that body weight reduction is central to reducing the risk of heart disease, stroke, type 2 diabetes, and certain cancers. Nevertheless, there is no official advice encouraging increased consumption of these foods in order to achieve and maintain a healthy body weight. Most importantly, there are no intervention studies that have tested the assumption that increased intake of fruit, vegetables and whole grain cereals will promote a healthier body weight. Our study will therefore address this issue to determine the effect of an increased intake of fruit, vegetables, and whole grain cereals on body weight, the intensity of effort required to achieve compliance, the durability of this habit, genetic determinants, and the effect on biomarkers of chronic disease risk.

We will ask approximately 780 families to take part in this study. We will invite households to take part if there is at least one adult who is eligible for our study, and who agrees to participate.

To be eligible for this study, participants must be at least 18 years old and have no medical conditions that would make it unsafe for them to take part. Before beginning the study, the medical history and other measures will be checked to ensure participant safety and suitability for participating in the study.

This study consists of three parts. If agreement to participate is given, the first part is to make an appointment to come to our study clinic to give a fasting blood sample (baseline measurements), about 40mL of blood. The clinic visit will last approximately 40 minutes. All participants will be asked to complete a short checklist about their medical history, which includes information to make sure that they and their household are eligible for participation. Body fat measurements will also be made using a non-invasive, very simple machine called Futrex as well as height, weight, waist-to-hip ratio, and blood pressure. Part of the blood sample will be used for a health screen to ensure subject safety and suitability for participating in the study. Blood samples will be stored in a secured location and analyzed at the end of the study for cholesterol levels and other risk factors for heart disease. Part of the blood sample will be used in DNA analysis to help us understand the genes related to food intake and metabolism. We will also ask all participants to complete a questionnaire package about their eating habits and their physical activity either prior to the clinic visit or at the end of the clinic visit. Once the questionnaires are completed and returned to the study office, the second part of the study will commence.

The second part is the intervention itself, lasting six months. If households are deemed to be eligible, they will be 'randomized' into one of eight study groups with all groups receiving Canada's Food Guide & Physical Activity Guide. The study groups involve a combination of different kinds of dietary advice and provision of fruit, vegetables, and whole grain cereals.