University of Calgary

U of C team publishes first-ever portion control study

 June 25, 2007


Diet plate helps diabetics drop pounds

A University of Calgary specialist has published her findings of a clinical study focusing on weight loss for people with diabetes in the June 25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. Endocrinologist Dr. Sue Pedersen’s paper finds that people with diabetes using a portion control tool lost as much weight as they would on medication, without the side effects.

“My study shows that this portion control tool is an effective way for diabetics to lose weight, which is encouraging since diabetics tend to have a very difficult time with weight control,” says Dr. Pedersen. “The weight loss we saw is similar to studies using weight loss medication, but without the potential side effects, or the expense.”

130 people with Type 2 diabetes participated in the six-month randomized control trial, titled Portion Control Plate for Weight Loss in Obese Patients with Type 2 Diabetes Mellitus. 17% of participants using the diet plate lost 5% or more of their body weight, a clinically important amount of weight. 4.6% of people in the control group lost 5% or more of their body weight.

“If you are overweight, losing 5% of your body weight is clinically significant because this decreases your risk of obesity-related diseases such as cancer and heart disease, and, decreases your risk of dying from obesity,” says Dr. Pedersen, who practices as a specialist in endocrinology and metabolism in Calgary and Saskatoon.

26% of study participants using the portion control tool were able to decrease their use of diabetic medications as compared with 11% in the control group. Conversely, 34% of participants in the control group required an increase in treatment for their diabetes as compared with 14% in the diet plate group. 

“I was thrilled to be chosen for this study. I have such problems with carbohydrates,” says Calgarian Sharon Zentner. “The diet plate made me stop and think about my portions in pasta, rice, and red meat. I realized I didn’t need all the extra fats and carbs that I was putting into my system. It taught me to eat slower and enjoy every mouthful.” She lost 20 pounds and 4 inches from her waist over the six-month period and was able to stop the medication she had required to control her diabetes.  She continued using the plate for a year after the study, and today she remains a diet-controlled diabetic, free of diabetes medications.

With portion sizes increasing by 2 to 5 times over the past 20 years, Dr. Pedersen chose to investigate portion control. “I find that most people know what constitutes a healthy food choice,” she says, “But controlling portions and eating balanced meals present a problem.”

The diet plate has painted lines to help people measure their portions of carbohydrates, proteins, cheese and sauces. It allows unlimited vegetables with the exception of peas, carrots, corn and potatoes. The diet bowl also has colourful painted lines to spell out a portion of breakfast cereal, with different measurement levels for different cereals.

Dr. Pedersen stresses that this portion control tool would be likely to be useful for anyone who wants to lose weight. “Improvement should be seen if people use the tool properly,” she says.

U of C’s Dr. Greg Kline and Jian Kang, MSc, were the second and third authors of this study. The Stewart Diabetes Education Fund funded the study while the UK-based company, The Diet Plate ®, donated the portion control tools. 

For interviews contact Rhonda Watson, 403.210.3835,
For more information contact Dr. Sue Pedersen,