Quick—without looking at the nutrition label, how many servings are in a small bag of potato chips? The answer, on average, is 2.5! You’d be forgiven for assuming that one small bag equals one serving because it’s packaged as a single unit. However, understanding the difference between serving sizes as listed on packaging and portion sizes appropriate for your body and dietary needs can be a major step towards better health.
“People look at the serving size and their initial interpretation is that is the appropriate portion,” said Gillian Arathuzik, R.D., L.D.N., C.D.E., nutrition diabetes educator at the Joslin Clinic. Gillian also works with people to improve their diets in the Why WAIT program, and was a co-author of the Diabetes Breakthrough. “That’s the biggest misconception,” she continued. “If they picked up a box of cereal and it says ‘One cup,’ they automatically assume that they should have one cup of cereal, whether that’s right, wrong or otherwise.”
It goes the other way, too. When Gillian asks patients how much cereal they have, the standard, across-the-board answer is “one cup,” even if they’ve never measured and don’t truly know.
Part of the problem with this method is that serving sizes are set arbitrarily by the company making the product. For example, they prefer for their labels to indicate their cereals are calorically-comparable so they’ll list a calorie dense cereal serving size as a quarter cup, whereas a lighter puffed-rice type cereal might be listed as a cup and a half.
Recently proposed changes to the food label should help clarify—they’re supposed to reflect what people actually eat. “If it’s a single bag of chips it needs to say there’s 300 calories in this whole bag of chips, not [2 servings with] 150 per serving, because really you’re going to eat the whole bag,” said Gillian.
Even the most vigilant can get tripped up with tricky food labels.
“So here I teach this,” said Gillian, “and the other day I bought these muffins and I was psyched because they were these good sized muffins and they were 150 calories and I thought ‘amazing!’ I’d eaten 2 of the four, I went to eat the third on a different day and I looked at it and realized that was only half the muffin! I’ve been a dietitian since 1998; how did I miss this?”
Gillian says these kinds of slips can stem from magical thinking or skimming labels too quickly. “I think I just read it too quickly in the store, didn’t take the time.”
So how can you separate your best portion size from the standard servings on the label? To get started with a healthier lifestyle, try out the plate method—fill half your plate with vegetables, a quarter with protein, and a quarter with carbs. You can ease yourself into the reduced portions with a third of the plate filled with each nutrient, which will still lead to reasonable portions.
“Eyeballing is obviously for the birds,” says Gillian. Break out your measuring cups and spoons, and use a food scale for items listed by weight. If you need something quick, buying pre-portioned snacks (like single-serving hummus packages) will help keep you to appropriate helpings. (If you need to eyeball, though, try comparing your portion to common household items, using these photos as a guide.)
“Generally we recommend between 30 and 60 grams of carbohydrate for someone looking to lose weight with diabetes,” she said. You can use Joslin’s food choice list (above)to help guide your portions, which shows food choices in 15g carb increments.
Do you need help managing your diet? Learn more about the Joslin Nutrition Programs.