Portion Control: It Works

People's waistlines have increased right along with the increasing sizes of food servings in restaurants. Portion control, then, is just one of the tools advocated for successful weight loss. "A four-ounce serving is about the size of your palm," says the dietitian. Yet there's no actual research showing that portion control alone will help with weight loss. Enter researchers at the University of Calgary in Alberta, Canada, who devised a study to test that very assumption (Arch Intern Med 2007;167(12):1277-1283).

They used a nifty portion control tool called "The Diet Plate," which is a dinner plate decorated with outlines for appropriate servings of a dinner meal: carbohydrates, proteins, cheeses, sauces, and vegetables. "The Diet Plate" also comes with a cereal bowl with concentric rings painted around the inside, which indicate appropriate servings of various types of dry cereal.

For the study, the scientists recruited 122 obese men and women. All had type 2 diabetes, but only 40% of the subjects were diabetics using insulin to manage their blood sugar. Approximately half of the test subjects were given a Diet Plate and cereal bowl and taught how to use them. They were told to use the cereal bowl whenever they ate cereal for breakfast, and to use the Diet Plate for their largest daily meal, when they ate at home. Subjects were also instructed not to eat more than usual at other times of the day. The other half of the test subjects acted as the control group: they received their usual care from their doctors and dietitians.

In the six months of the study, those using the calibrated plates and bowls lost "significantly more" weight than those who were in the control group. In fact, those who lost weight using the tools lost between 1.8% and 5.7% of their body weight - which is equivalent to a 300-pound man losing between 5.4 and 17.1 pounds (remember that all of the test subjects were clinically obese). These results are comparable to the results seen in studies of prescription weight loss medications.

What this means for you

What's really amazing about this study is that even those who were on insulin lost weight, and we doctors know that it's notoriously difficult for those who are on insulin to lose weight. If it will work for those who are on insulin, just sticking to standard portion sizes will work for someone who is otherwise healthy.

First posted: September 17, 2008