This is the question being asked by personal trainer Eric Briere, a question that he intends to put to the test over the next month. While his study design was not apparent from his short video, his hypothesis is clear - he will gain weight. His video has been receiving a fair amount of attention from the virtual community (>100 people Facebook "like" it), and I am concerned about the implications of his experiment.
Eating Well with Canada's Food Guide is an important resource for Canadians, providing basic information on the amount and types of food that should be consumed daily to meet nutrient needs and reduce the risk of certain chronic diseases. Given the dramatic increase in overweight and obesity over the last few decades, it is of the utmost importance that public health messaging be unambiguous and evidence-based. This can be difficult to achieve sometimes, which is understandably frustrating for the public who become increasingly cynical about public health recommendations. The issue of unclear, somewhat vague messages when it comes to dietary recommendations is an interesting one that is worthy of discussion. I will be sure to blog about this later, but for now, I just want you to think about your own diet. It is likely to vary considerably from one day to another, and to have changed over time. Are you able to clearly and accurately describe your lifetime exposure to food and nutrients?
Back to the matter at hand - did Health Canada overlook caloric intake when developing Canada's Food Guide? The answer is no. The paper describing the development of Eating Well with Canada's Food Guide can be found on Health Canada's website. The portion sizes and specific recommendations for each Food Group (ie. eat at least one dark green and one orange vegetable each day) were empirically-derived from Canadian data. The food intake patterns were assessed using 500 simulated diets for each age / gender group. The criteria for energy needs is described below.
"The median energy content of simulated diets should be at or below the Estimated Energy Requirement (EER) calculated for reference individuals using a sedentary level of activity. Measured heights and weights from the Canadian Community Health Survey, Cycle 2.2, were used to determine median height and median normal weight for each age and gender group. These were then used as inputs to the EER equations. A sedentary level of activity was considered most appropriate so that there was no overestimation of requirements."
For most age / gender groups, the median intake was within or below the median EER range with some exceptions (Males 71+, Females 9-13, 14-18, 51-70, 71+). Keep in mind, the median EER range was determined for sedentary persons, and would need to be multiplied by a physical activity coefficient to be compliant with the recommended physical activity levels of Eating Well with Canada's Food Guide (30-60 minutes per day for adults).
As an example, the median EER range for sedentary males 31-50 years old was 2250-2450kcal/d. To convert the EER to align with the recommendations for physical activity in Eating Well with Canada's Food Guide you must multiply the EER by a physical activity coefficient of 1.11. In this case, the range in median EER becomes 2498-2720kcal/d, which exceeds the 90th percentile of energy intake based on the simulated diets adhering to the food guide (2406kcal/d).
This being the said, you might ask yourself why I am worried about Eric Briere's experiment. Based on the data for 31-50 year old males, he is more likely to lose weight than gain it, right? The problem is that he may not be following Canada's Food Guide.
The food intake pattern that became Eating Well with Canada's Food Guide includes the within food group recommendations to "make each food guide serving count...". His suggestion that he will eat 10 bananas a day to meet his fruit and vegetable requirement does not adhere to the recommendation to "eat at least one dark green and one orange vegetable each day".
Moreover, with things like bananas, size matters. Given the diversity within foods like bananas and bagels (his other example), it is necessary to consider the actual amount to obtain an accurate estimate of servings. Portion distortion is common, and explains the misconception that it is difficult to meet daily requirements for Fruits and Vegetables and Grain Products.
That being said, it is certainly possible to adhere to the food guide and gain weight (particularly if you are trying to make that point). Emphasizing energy-dense foods like avocados and nuts within each food group and being sedentary would almost guarantee weight gain.
His study is interesting and has important implications, and I look forward to seeing the results. If his hypothesis is confirmed (he gains weight), it will indicate that we should re-evaluate the methodology used develop Canada's Food Guide, and its appropriateness for use as a public health resource. There is considerable measurement error, both in estimating energy expenditure and predicting energy intake for a population following a food guide, so his research question is a good one. To my knowledge, Eating Well with Canada's Food Guide has not been subject to a validation study in free-living subjects. However, if he does not comply with the food guide, consume his usual foods, and maintain his physical activity level, his study will not address his research question, and the message of weight gain that is conveyed to his clients and the viral community may do undeserved, irreparable damage.
For those of you that are also following his progress, I encourage you to read the paper explaining the development of Eating Well with Canada's Food Guide. For those interested, as I have been looking to conduct an n=1 study on myself, I will be repeating his experiment. Because I am biased, I am going to do my best to remove myself from the equation, and be as transparent as possible.
Using foods / meals that I regularly eat, I developed a 7-day food record and analyzed it using the USDA nutrient database. Throughout the month, I will record my physical activity, and weigh myself every Monday morning, wearing the same clothes, in a blinded manner (someone else will record my weight).
If you have any suggestions of how to further improve this study, please let me know as soon as possible so that I can incorporate them.
Thanks for your interest.
Katamay SW, Esslinger KA, Vigneault M, et al. Eating Well with Canada's Food Guide (2007): Development of the food intake pattern. Nutrition Reviews 2007; 65(4): 155-166.
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