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Canada’s Food Guide may be associated with overweight, obesity
Recommendations for the consumption of meats, fruits and vegetables included in Canada’s Food Guide may be associated with increased BMI in adults, according to an analysis of Canadian Community Health Survey data.
“This study explores the relationship between dietary adherence (Canada's Food Guide) and overweight/obesity in adults at the national level in Canada, and finds that participants who met the minimum servings in vegetables and fruit had a lower measured BMI,” Helen So, PhD, a health economist in the department of medicine at the University of Alberta in Edmonton, Canada, told Endocrine Today. “Also, participants who met the minimum servings in meat and alternatives had a higher measured BMI.”
The current food guide, released in 2007, provides Canadians with recommendations on the types and amounts of food an individual should consume daily according to age and sex, according to study background; however, no study has explored the relationship between adherence to the food guide and overweight and obesity in adults at the national level, the researchers noted.
Men aged 19 to 50 years, for example, should consume eight to 10 servings of vegetables and fruit daily, along with three servings of meat and alternatives, whereas women in the same age group should consume between seven and eight fruit and vegetable servings and two servings of meat and alternatives, according to the guide.
So and colleagues analyzed data from 6,202 adults participating in cycle 2.2 of the Canadian Community Health Survey, administered in 2004-2005 (mean age of men, 40 years; mean age of women, 41 years; 84% white; mean BMI, 26 kg/m²; 21% with obesity). The national survey, administered by Statistics Canada and Health Canada, included a modified version of the U.S. Department of Agriculture’s 24-hour dietary recall; all participants self-reported height and weight before being measured by an interviewer. All major food items were categorized into four predetermined food types stated in Canada’s Food Guide: vegetables and fruits, grain products, milk and alternatives, and meat and alternatives. Food items recorded in grams in the data were converted into number of servings per day in the four food groups, using serving sizes listed in the Canadian Nutrient File. Researchers used linear regression analysis to assess the association between measured BMI and Canada’s Food Guide adherence.
Researchers found that most survey participants did not meet Canada’s Food Guide minimum number of servings suggested in three of the four categories. In 24-hour dietary recalls, 29% of respondents met the minimum number of servings for vegetables and fruits, 46% met requirements for grain products, 40% met requirements for milk and alternatives, and 62% met requirements for meat and alternatives.
After adjusting for multiple factors, including sex, age, race, marital status, diabetes, hypertension, personal income, smoking and drinking status, and self-perceived health and mental health, researchers found that adherence to recommended serving amounts for vegetables and fruit was negatively associated with measured BMI among the entire cohort (coefficient, –0.593; 95% CI, –1.104 to –0.082), whereas adherence to recommended serving amounts for meat and alternatives was positively associated with measured BMI (coefficient, 0.621; 95% CI, 0.128-1.114) .
In results stratified by sex, similar results for meat and alternatives were observed for women only, according to researchers. In results stratified by BMI category, the association between measured BMI and vegetables and fruits and meats and alternatives persisted among participants with overweight and obesity, but not among those of normal weight.
“Since [Canada’s Food Guide] did not provide the maximum number of servings, this paper could not determine whether this association was due to over-consumption in meat and alternatives or not,” the researchers wrote. “In addition, because of the nature of the survey data, there might be other factors that the survey did not account for, but still influenced the relationship between meat consumption and BMI. ... As such, this relationship needs to be validated in future studies using longitudinal data.”
The researchers did not observe any associations between the grain and the milk and alternatives food groups and BMI.
"The reasons [for no association] are not clear, but the consistency across our models suggests that the absence of association may be robust,” the researchers wrote. – by Regina Schaffer
For more information:
Helen So, PhD, can be reached at the dDpartment of Medicine, University of Alberta, TRW-GE57, 3280 Hospital Dr NW, Calgary, Alberta, Canada T2N 4Z6; email: hso1@ualberta.ca.
Disclosures: The authors report no relevant financial disclosures.