Portion-Control Tableware Helps Obese Diabetics Lose Weight

CALGARY, Alberta, June 25 -- A plate and a cereal bowl marked for a portion size designed to limit calorie intake helped obese diabetic patients know when enough is enough, researchers reported.

After six months, patients with type 2 diabetes who used the tableware were more than 3.5 times as likely to have lost at least five pounds as were patients given usual care, Sue D. Pedersen, M.D., of the University of Calgary, and colleagues, reported in the June 25 issue of the Archives of Internal Medicine.

In addition, the patients using portion control were able to safely decrease their glycemic-control medications, the researchers reported.

The number of calories ingested by patients at a meal has been directly correlated with the serving size, Dr. Pedersen said.

However, the researchers knew of no published clinical trial that has examined the efficacy of using portion-control tableware to induce weight loss and improve glycemic control.

The portion-control dishes included a calibrated dinner plate that was sex specific and a breakfast bowl, which was not. The man's plate was calibrated for an approximately 800-calorie meal; the woman's plate provided a 650-calorie meal.

The cereal bowl allowed for a 200-calorie meal of cereal and milk.

To facilitate portion control, the plate is divided into sections designed to contain predetermined volumes of carbohydrates, proteins, cheese, and sauces, with the remainder of the center of the plate open for vegetables.

For mixed meals that could not be readily divided into the respective macronutrient sections, food was assigned to the section that represented the meal's dominant macronutrient, the researchers explained.

Patients kept logs and were instructed to use the calibrated plate for their largest meal of the day, to use the cereal bowl when cereal was eaten for breakfast, and not to compensate for portion control by eating more at other times.

The researchers randomly assigned 130 obese patients (mean age 56; 77 women) with a body mass index of at least 30 kg/m² and type 2 diabetes (including 55 patients taking insulin) to one of two groups.

Sixty-five in the intervention group used a portion-control plate for six months, while 65 in the usual-care control group received standard dietary instruction.

Patients were enrolled from April 1, 2004 through June 30, 2004 and were recruited from an outpatient diabetes center in Calgary.

At the six-month visit, patients in the intervention group lost 1.8% of their body weight versus 0.1% among the controls (P=0.006), the researchers reported.

A significantly greater proportion of the intervention group, 16.9% (11 patients), lost at least 5% of their body weight compared with 4.6% (three patients) of the controls (P=0.048).

The researchers noted that a 5% weight loss has been shown to be clinically significant in terms of decreasing the morbidity and mortality associated with obesity-linked disorders such as cancer and myocardial infarction.

Also at six months, 17 patients in the intervention group were able to decrease their diabetes medications versus seven controls (26.2% versus 10.8%, P=0.04) without sacrificing glycemic control, the researchers reported.

Among insulin users, the portion-control patients recorded a significant decrease in daily insulin (-8.4 U); patients in the control group needed more insulin (+7.2 U) (P=0.02).

These results, the researchers said, are comparable to those of several studies using pharmaceutical intervention for weight loss in type 2 diabetes.

Study limitations included poor compliance with the intervention. Among 53 patients who kept a log, median compliance was 70.8%.

Also persons who ate most of their meals away from home were excluded from the study, perhaps motivating patients who want to lose weight with this tool to eat at home as much as possible, the researchers suggested.

In conclusion, the investigators wrote, the portion-control tool was effective in inducing weight loss comparable to that seen in studies of drug therapy for weight-loss and in enabling patients to cut back on hypoglycemic medications.

This intervention, they said, holds promise for use in all overweight patients, whether they have diabetes or not.