Despite what these programs tell you in their commercials, few of them have actually conducted clinical research studies to test their effectiveness. Two new weight loss studies, published online in the Journal of the American Medical Association and free to download, examined the effectiveness of structured weight loss programs in different groups of volunteers.
In the first weight loss study, investigators assigned 442 overweight or obese adult women with a BMI of 25-40 to a center-based weight loss program, a telephone-based weight loss program or usual care[1]. The usual care group was provided consultation and information at the start of the study and again at 6 months. The volunteers assigned to the center-based and telephone-based weight loss programs received pre-packaged prepared foods and all necessary program materials. Additionally, they received in-person or telephone-based diet counseling on a weekly basis as well as access to website or message board interaction. Study volunteers were encouraged to consume about 40-70% of their food intake from the pre-packaged meals during the first six months of the study and then transition to a mainly food-based meal plan over the remaining 18 months. Additionally, study volunteers were asked to exercise 5 days per week for 30 minutes. The results of this study showed that:
Individuals in the usual care group lost about 7 pounds and 2 inches over 2 years.
Volunteers in the center-based structured weight loss program lost about 18.5 pounds and nearly 3.5 inches over 2 years.
Subjects in the telephone-based structured weight loss program lost about 15 pounds and 3 inches over 2 years.
In the second weight loss study, investigators examined the usefulness of a structured weight loss program for severely obese individuals (average body mass index was about 43-44) [2]. For this study, 130 severely obese volunteers were randomly assigned to a structured weight loss program that included either exercise that began at the start of the study or exercise that didn't begin until 6 months into the study period. The structured weight loss program consisted of a combination of group, individual, and telephone contacts over a 1 year period. Study volunteers were asked to follow a meal plan that included 2 meal replacements per day during the first 3 months and 1 meal replacement from months 4 through 6 and were asked to briskly walk for 60 minutes 5 days per week. The investigators reported:
On average, volunteers that started exercising at the start of the structured weight loss program lost about 27 pounds, 4 inches off their waist, and about 17 square inches of belly fat.
Volunteers that started walking six months into the structured weight loss program lost on average 22 pounds, 3 inches off their waist, and about 14 square inches of belly fat.
78% of individuals in the initial-activity group lost more than 5% of their body weight after 1 year, while 65% of the delayed-activity group lost more than 5% of their body weight.
Overall, these two weight loss studies indicate that a well-structured weight loss program can be an effective weight loss tool for adults who are overweight, obese, or even severely obese. A structured weight loss program can make it easier for individuals to follow by offering pre-packaged meals or meal replacement bars and shakes, which helps minimize food weighing and calorie counting. This can make it easier for individuals to stick to a diet plan. This was clear in these studies where compliance to the diet plans was 78% in one study and 92% in the other study. Because of the effectiveness of structured weight loss programs, the investigators of each study and the author of an accompanying editorial[3] suggest that health care systems should consider their incorporation. While this will likely not happen on a regular basis in the immediate future, well-structured weight loss programs are available for those interested in healthy weight loss. Make sure to look for weight loss programs that are clinically tested, easy to follow, and provide a good diet counseling support system.