This study evaluated the importance of attendance in group appointments for weight loss for Type 2 diabetes risk reduction in normoglycemic men and women aged 25 to 50 years, with a body mass index(BMI) of 27 to 35 kg/m2, The single-group 24-week intervention consisted of food, activity, and behavior modification plans within weekly meetings. Weight, waist circumference, meeting attendance, and glucose handling were measured before and after. Meeting attendance was correlated with decreases in weight, BMI, and waist circumference. Commercially available programs with weekly group meetings can be effective in reducing Type 2 diabetes risk for overweight and obese adults, but attendance is critical.
The worldwide prevalence of overweight and obesity has risen dramatically in the past 20 years.
For example, in the United States, an estimated 66% of adults are either overweight or obese, affecting all segments of the population. Many risk factors and significant medical conditions are associated with overweight and obesity. In the past 2 decades, the prevalence of diabetes has also increased dramatically. A particularly strong association exists between obesity and Type 2 diabetes. Independent of body weight, accumulation of excess visceral abdominal fat has been shown to carry independent risk for the development of Type 2 diabetes and metabolic syndrome.
Subtle forms of glucose intolerance may occur in obese individuals prior to the onset of actual diabetes. Several recent national and international trials have demonstrated that lifestyle interventions such as nutritional and physical activity counseling may prevent up to 58% of diabetes in overweight or obese individuals with glucose intolerance and may even be more effective than pharmacological treatment.
Although interventions to prevent diabetes carry great potential benefit, the cost of implementation may be substantial. In the Diabetes Prevention Program (DPP) trial, for example, the estimated direct medical costs over 3 years for the lifestyle intervention program exceeded the costs of placebo by approximately $2,269 per individual. In addition, indirect costs and direct nonmedical costs for the lifestyle intervention exceeded those of the placebo group by $1,271 per person. Thus, the total direct and indirect costs to provide the lifestyle intervention arm of the DPP exceeded the placebo arm by more than $3,500 per individual. In addition, prevention programs tested in clinical trials to date have been more intense than would be likely feasible in a real-world setting. This level of expense and intensity is unlikely to be acceptable to individuals with glucose intolerance outside of the setting of a federally funded study.
Behavioral therapies including various forms of behavioral modification (eg, self-monitoring, cognitive restructuring, social support) in combination with education regarding food and physical activity are the most widely used forms of treatment for weight loss. In real-world settings, many obese individuals undertake such treatment in the context of a commercial weight loss program, so an evidence base is needed regarding these. Previous reports have shown that participation in a commercially available comprehensive weight management program can result in significant weight loss, improved body composition, reduction of risk factors for a variety of chronic diseases, and improvement in quality of life for the group as a whole.
Active participation in support groups may be an important predictor of weight loss success. In one previous report from a multicenter trial comparing a commercially available weight management program to self-help, improved weight loss was found with the structured commercial program over a 2-year period. Of note, participants in this study who attended 78% or more of the commercial group sessions maintained a mean weight loss of almost 5 kg at the end of the 2-year study. This degree of weight loss has been associated with significant reductions in the likelihood of developing Type 2 diabetes among obese individuals with glucose intolerance.
Previous investigations have demonstrated that group support represents an effective component of a comprehensive approach to weight management. Direct comparisons are lacking between attendance at group meetings and weight loss, waist circumference, and insulin resistance in overweight or obese individuals as part of a Type 2 diabetes prevention program, although this real-world research is critically needed. Thus, the objective of this analysis was to evaluate results of such a program specifically with regard to its impact on diabetic risk factors and to what extent attendance might modify any impact. The main hypothesis was that attendance would be directly related to risk reduction for Type 2 diabetes.
This was a 24-week single-group clinical trial with outcomes measured before and after. The primary outcome measurements were weight loss (kg) and participants had to be willing to commit to participation in a commercially available weight loss program that included attending weekly group meetings. Individuals with established diabetes or coronary heart disease were excluded from participation in the study. In addition, individuals were excluded if they had a history of surgical procedures for weight loss, weight loss of more than 5 lb for any reason within 30 days prior to potential enrollment, uncontrolled high blood pressure, any significant gastrointestinal disorder, history of a clinically diagnosed eating disorder, currently engaging in more than 150 minutes or more of dynamic physical activity every week, or women who were pregnant, lactating, or trying to become pregnant.
Subjects were enrolled in an internationally recognized program that combines a structured hypocaloric diet, an exercise component, and cognitive restructuring tools within weekly group meetings.
Participants received an initial 20-minute counseling session by a registered dietitian and an exercise physiologist from the research team. These sessions taught individuals how to fill out records for the purposes of data collection. Instruction in the comprehensive weight management program itself was delivered by trained leaders as part of the weekly meetings that participants were asked to attend. The multidisciplinary weight management program consisted of a food plan, an activity plan, and a behavior modification plan focused primarily on cognitive restructuring. The food plans were nutritionally balanced, moderate-deficit diets designed to result in a weight loss of up to 0.9 kg per week. The activity plan followed the current guidelines from the American College of Sports Medicine. Weekly group meetings lasting approximately 1 hour were led by successful graduates of this program who act as role models and provide written educational materials, social support, and a weekly weigh-in session. Attendance was taken at the weekly group meetings, although results of this attendance were not known to the research team until the conclusion of week 24 data collection. Individuals who missed more than 2 consecutive weeks were sent reminder cards by the group leader.
Subjects were assessed in the research laboratory at baseline and again at 24 weeks. Baseline determinations included complete blood count, blood chemistry panel (SMAC-12), urinalysis, lipid profile, C-reactive protein, and blood pressure. BMI was calculated from fasting weight and height measures, and waist circumference was measured using standardized techniques.
A standardized 2-hour oral glucose tolerance test (OGTT) was also performed to assess responses to a glucose challenge. Insulin sensitivity and glucose disposal were determined using the respective AUCs and standardized homeostasis model assessment of insulin resistance (HOMA-IR) during the OGTT.
Over the 6-month study period, a total of 61 individuals were enrolled in the comprehensive weight loss program.
The main finding of this study was that if normoglycemic overweight and obese adults attend at least 65% of weekly group meetings in a multidisciplinary weight loss program, risk for Type 2 diabetes can be significantly reduced. The program, which included plans for a hypocaloric diet, increased physical activity, and cognitive restructuring, also resulted in significant improvements in BMI, waist circumference, and body composition for individuals who attended the greatest percentage of group meetings. Benefits may be even greater with 82% attendance.
Numerous studies have supported the concept that comprehensive lifestyle management approaches to weight loss including structured food and activity plans and behavioral strategies such as group support are effective both for short-term weight loss and longer term maintenance of weight loss. The data presented here specifically demonstrate that individuals who participate in the highest percentage of group meetings achieve the greatest degree of weight loss, decrease in waist circumference, and improvement in glucose handling.
Such dose-response results can serve as motivators for individuals who would otherwise tend to skip meals. Previous studies have shown that lifestyle interventions are highly effective in reducing the incidence of Type 2 diabetes in obese individuals. These studies, which focused on individuals with baseline insulin resistance, show that lifestyle interventions that resulted in weight loss comparable with those reported in the current investigation are effective in at-risk populations for lowering the incidence of Type 2 diabetes.
The present findings extend the results of previous studies because this population of obese individuals had normal fasting blood glucose and showed significant improvement in insulin resistance along with weight loss. These benefits were strongly associated with meeting attendance when the data were analyzed both categorically and continuously.
Research has shown that a variety of behavioral strategies involving maintenance groups can serve as effective components of comprehensive weight management. This study further supports the value of such maintenance groups and provides more specific information concerning the relationship between meeting attendance and both weight loss and glucose handling. While the current study explores social support in the context of a commercially available group meeting, it is likely that expanding the circle of support (i.e., to include family, friends, coworkers, etc…) may enhance the findings.
The dramatic rise of overweight and obesity worldwide, along with the associated sharp increase in the prevalence of diabetes, mandates innovative approaches to helping people lose weight and improve early stages of abnormalities of glucose handling.
Data presented herein suggest that a widely available commercial weight loss program can fill that mandate. A particularly attractive potential benefit of the current study relates to the economic efficiency of commercially available programs.
In addition to money, time is an important consideration, because most clinical health professionals have limited time to devote to individuals who would benefit from a weekly 1-hour diabetes prevention program. The program in the current study was implemented by trained successful program completers who were able to devote the time required for social support, weigh-ins, and plans relating to a hypocaloric diet, physical activity, and cognitive restructuring behavior modification.
This study has shown that group appointments can be effective in improving the ability to increase weight loss thereby decreasing the risk for diabetes or improving diabetes control.
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American Journal of Lifestyle Medicine, Vol. 4, No. 3, 275-281 (2010) DOI: 10.1177/1559827609361013 This version was published on May 1, 2010.
Kathleen J. Melanson, PhD, RD, LD; Department of Nutrition and Food Sciences, University of Rhode Island, Kingston, firstname.lastname@example.org
Joshua Lowndes, MA; Center of Lifestyle Medicine and Department of Health Professions, University of Central Florida, Orlando