July 30/New York/Applied Physiology, Nutrition and Metabolism -- Many people overestimate the size of one serving of food as defined in Canada's Food Guide, so they may be overeating even if they believe they are being careful, according to a study by Jennifer Kuk, a professor in the School of Kinesiology & Health Science in York's Faculty of Health, and lead author Sharona Abramovitch, a former graduate student at York.

The study was published online in the journal Applied Physiology, Nutrition and Metabolism.

Canada's Food Guide is an important tool used by many general practitioners to help their patients eat more healthfully, says Kuk, so it made sense to study whether people would be able to tell from the food guide if they are eating enough of the four food groups: vegetables and fruit, meat and alternatives, grain products, and milk and alternatives.

"What we found was that the way people estimate one serving is essentially how much they would normally eat at one time," says Kuk. "The majority of participants in the study inaccurately thought they would need to increase their food consumption by approximately 400 calories to meet recommendations in Canada's Food Guide. This suggests we either need to change the size of a serving in the Guide -- which has remained almost the same since 1977 -- or educate Canadians more about how much food they should be consuming in a day."

That 8oz. steak on the barbeque this summer, for example, alone exceeds the Canada Food Guide's maximum daily allowance for meat and alternatives, says Abramovitch, a former graduate student in the School of Kinesiology & Health Science in York's Faculty of Health. And only half a cup of cooked pasta is one of the eight grain servings allowed per day for a male between the ages of 19 and 50.

Researchers analyzed food records from the 145 participants in the study, which included White, Black, South Asian and East Asian adults. They were asked to select what they thought was a serving, and researchers measured it to see whether the serving size corresponded with Canada's Food Guide. They were also asked to estimate how much of something -- for example, pasta -- they would eat at one sitting, and to recall their diet over 24 hours. All four ethnic groups inaccurately estimated the total number of servings they were eating in a day: they underestimated the number of servings of fruit and vegetables, grain products and meat and overestimated the number of servings of milk and alternatives they were eating.