Food Habits of Canadians: Reduction in Fat Intake over a Generation
Gary-Donald, Katherine, Jacobs-Starkey, Linda, Johnson-Down, Louise, Canadian Journal of Public Health
The role of diet in the prevention of chronic disease is well established: fruit and vegetable consumption has a strong protective effect on the development of cancer at numerous sites; saturated fat intake is clearly associated with coronary heart disease;2 and the total direct cost of obesity in Canada was estimated to be $1.8 billion for 1997.3
In the U.S., the National Health and Nutrition Examination Surveys and the Continuing Survey of Food Intake of Individuals4 provide useful data on nutritional intake and food trends.', These data show a downward trend in energy intake levelling off in the 1990s, but total fat consumption continuing to decline from 42% of energy intake in 1965 to 33% in 1995.2 The most recent national data in Canada derive from the Nutrition Canada survey (1970-72) conducted a generation ago.67
Four provincial surveys were completed more recently. The Ontario" and Manitoba" surveys used semi-quantitative food frequency questionnaires while the Nova Scotia" and Sante Quebec surveys" used 24-hour recalls which provide quantitative measures of dietary intake. Total fat intakes have declined but remain above the recommended 30% of energy and low intakes of calcium, iron and folate were identified for specific age-sex groups.11,12 National data estimated from Canada's family food expenditure survey also indicare declines in total fat content of foods purchased. 13
Our survey "Food Habits of Canadians" provided data between August 1997 and July 1998 in five regions of Canada (Atlantic, Quebec, Ontario, Prairies and British Columbia) on current food and nutrient intake. This report focusses on current nutrient intake and compares these data to earlier studies.
The sampling of respondents (18-65 years and adolescents 13-17 years) was done using a multi-stage random sample of adult Canadians living in five regions of Canada: Atlantic (New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland), Quebec, Ontario, Prairies (Manitoba, Saskatchewan, Alberta), and British Columbia. Fifteen percent of the Canadian population who lived in regions far from major population centres were not sampled. Aboriginal communities were not included. In each region, four Canada census divisions were randomly chosen with a probability proportional to the population. For each of the 20 divisions, a random sample of two subdivisions was similarly selected, and for each subdivision, two enumeration areas were selected, resulting in 80 enumeration areas across the country. Boundaries of enumeration areas were identified using Statistics Canada maps and address ranges within an enumeration area. The sampling for individual random households from within each enumeration area was done using the 1996 computerized telephone directory (Pro CD Inc., Mass.). Each household received a personalized letter to explain the study prior to telephone contact. Interviewers attempted to enrol one adult per household (the adult with the next birthday) for a total of 20 adult respondents from each enumeration area.
Appointments for interviews were made on different days of the week including weekends. Interviews were held in the respondents' homes or at other convenient locations. A repeat 24-hour recall was conducted on 30% of the adult sample within approximately one week of the initial interview in order to estimate intra-individual variability.
Each adult participant was asked whether there was a potential adolescent (13-17 years) participant living in the household. The adolescent sample was not proportional to the population and is not independent of the adult sample.
Dietary intake was measured using the 24-hour recall, commonly used for national surveys.',112 A single 24-hour recall is an appropriate method to assess the average intake of a large group of individuals provided all days of the week and seasons are covered."," Interviews were conducted in French or English by professional dietitians who received a two-day training session in Montreal. …