Serving sizes are a reference amount of food to help consumers gauge how much they should eat from each of Canada’s four food groups (or other country’s food reference guides – healthy plates, pyramids, steps, even spinning tops in Japan!).  Sounds pretty simple, right?  This is where things get a little murky – consumers are consistently overestimating what actually makes up a serving size when compared to say, Canada’s Food Guide.  In fairness, it’s not all on the consumer if you consider a common bagel size is about 113 g whereas Canada’s Food Guide quotes half of a 90 g bagel as 1 serving of grain products.  This is a problem.

Researchers out of York University in Toronto decided to look into this very issue and studied about 150 people to determine the accuracy in which they could estimate serving sizes.  The results showed, overwhelmingly, that their subjects tended to overestimate serving sizes.  In fact, many of the study’s subjects thought they should increase their caloric intake in order to meet the food group serving recommendations of Canada’s Food Guide.  All of this may lead to overeating and we all know where that’s headed – weight gain.

Many pictorial representations of serving sizes are available to help people gauge their portions – baseballs, thumb, palm of your hand, deck of cards…  There are even plastic food models to help dietitians illustrate these confusing serving sizes.

Here’s the breakdown:

  • Closed fist = 1 cup (rice, veggies, cereal, fruit)
  • Palm of your hand = 3 ounces (meat, fish, poultry)
  • Thumb = 1 teaspoon of fat (vegetable oils)

In talking to many of my patients, these illustrations and props can definitely help people gauge their portion sizes better than weighing or measuring out their food (something I am generally not a fan of).  When you get a better sense of what properly portioned food looks like on your plate or in your bowls you get better at “eyeballing” or estimating your food choices.  Can this help us on our way to healthier eating?

There are definitely other factors that weigh in here, like the size of your plate, whether you’re eating with someone who eats more or less than you, the ambience of the room you’re eating in, whether you’re distracted (i.e. TV on), your emotions and so on.  Next time, we’ll explore some of these factors and how they can affect the over 200 food decisions we make a day.