NUTRISYSTEM-D AS A LIFESTYLE INTERVENTION Bruce Daggy, Ph.D., Anthony Fabricatore, Ph.D., Meghan Nichols, R.D., Amy Samuelson Ph.D.

Transcription

1 NUTRISYSTEM-D AS A LIFESTYLE INTERVENTION Bruce Daggy, Ph.D., Anthony Fabricatore, Ph.D., Meghan Nichols, R.D., Amy Samuelson Ph.D. This article reviews the recommendations of lifestyle intervention for the prevention and management of diabetes, and describes the Nutrisystem-D Program in the context of these recommendations. Nutrisystem-D Program Information All Nutrisystem weight loss programs provide home delivery of shelf stable or frozen meal entrées, snacks and desserts. These items, when complemented with grocery additions (including fruits, vegetables and low fat dairy products), result in structured meal plans that are hypo-caloric, portion-controlled, low in glycemic index, and consistent with national guidelines for general adult nutrition. The Nutrisystem structured meal plans are combined with educational support and monitoring tools to assist members in adopting long term healthy lifestyle habits. Multiple peer reviewed clinical studies have demonstrated that the use of portion-controlled meal programs result in better short-term weight loss among obese persons, when compared with diet plans designed to deliver an equivalent number of calories (Jeffery et al., 1993; Ditschuneit et al., 1999; Heymsfield et al., 2003; Hannum et al., 2004; Hannum et al., 2006; Wadden et al., 2007). Benefits for weight loss also have been observed in patients with type 2 diabetes who consume portion-controlled meal programs, compared with those who attempt to follow isocaloric self-selected diets. (Cheskin et al., 2008, Yip et al., 2001). Nutrisystem-D is a weight loss program specifically designed to produce gradual, realistic, and clinically meaningful weight loss in overweight and obese patients with type 2 diabetes. Further details of the program s design and effectiveness are given below, in the context of national guidelines. The Role of Weight Control in the Prevention and Management of Type 2 Diabetes Several professional and scientific organizations recognize the importance of weight loss for the prevention and management of health complications, including type 2 diabetes, in obese and overweight individuals. The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH), for example, concluded that a 5 to 7% reduction in initial weight (e.g., 10 to 14 pounds for a 200-pound person) can significantly reduce obesity-related risk (National Heart, Lung and Blood Institute Obesity Education Initiative, 1998). This statement was supported by the Diabetes Prevention Program (among other trials), which found a 58% reduction in the incidence of type 2 diabetes with a modest (~7%) weight loss among participants with impaired glucose tolerance (DPP Research Group, 2002). The Look AHEAD Trial: The NIH is funding a multicenter randomized trial of the effect of modest intentional weight loss on cardiovascular morbidity and mortality in persons with type 2 diabetes. Look AHEAD (Action for Health in Diabetes) is an ongoing investigation that includes over 5000 overweight and obese patients with type 2 diabetes, who were years old at enrollment ( Participants, who will be followed for up to 13.5 years were randomized to receive an intensive lifestyle intervention (ILI), which was designed to help participants achieve and maintain a weight loss of at least 7% of initial weight, or diabetes support and education (DSE), which is essentially a control group that receives four educational sessions per year. The ILI included a dietary prescription of <30% calories from fat (<10% from saturated fat), and 15% calories from protein. To facilitate adherence, participants were offered portioncontrolled meal replacements. The exercise component of the ILI included a goal of achieving 175 minutes of moderate-intensity physical activity. To date, the study has produced more than 50 publications. At one year, the ILI group lost significantly more weight than the DSE group (8.6% vs. 0.7% of initial body weight, respectively) and achieved significantly greater fitness and improvements in HDL cholesterol. Compared with DSE participants, those who received ILI also demonstrated significantly greater reductions in the fasting blood glucose, HbA1c, blood pressure, triglycerides, albumin/creatinine ratio, and use of medication (to treat diabetes, hypertension, and other cardiovascular risk factors), than the DSE group (Look AHEAD Research Group 2007).

2 The American Diabetes Association (ADA), in its annual Standards of Medical Care in Diabetes emphasizes the importance of weight control in patients who have, or are at risk of, type 2 diabetes. Selected quotations from this position paper appear below. Because of the effects of obesity on insulin resistance, weight loss is an important therapeutic objective for overweight and obese individuals with prediabetes and diabetes. Short-term studies have demonstrated that moderate weight loss (5% of body weight) in subjects with Type 2 diabetes is associated with decreased insulin resistance, improved measures of glycemia and lipemia, and reduced blood pressure (ADA 2010, pg. S24) In overweight and obese insulin resistant individuals, modest weight loss has been shown to reduce insulin resistance. Thus weight loss is recommended for all overweight or obese individuals who are at risk for diabetes. (ADA 2010, pg. S23) Among individuals at high risk for developing type 2 diabetes, structured programs emphasizing lifestyle changes that include moderate weight loss (7% of body weight) and regular physical activity (150min/wk) with dietary strategies including reduced calories and reduced intake of dietary fat can reduce the risk for developing diabetes and are therefore recommended (ADA 2010, pg. S24) Some of the key therapeutic goals of diabetes management to which nutrition can contribute are further addressed in the ADA s 2010 Guidelines as noted below: Glycemic Control is fundamental to the management of diabetes. (ADA 2010, pg. S20) Lowering A1C to below or around 7% has been shown to reduce microvascular and neuropathic complications of type 1 and type 2 diabetes. Therefore, for microvascular disease prevention, the A1C goal for non pregnant adults in general is <7% (ADA 2010, pg. S19). Empirical Support for Nutrisystem-D for the Management of Type 2 Diabetes Foster et al. (2009) conducted a randomized controlled trial that compared lifestyle modification, including the Nutrisystem-D program, with diabetes support and education (DSE) in 69 patients with type 2 diabetes. After 3 months of their assigned treatment, participants who received Nutrisystem D achieved a 7.1% reduction in body weight, compared with 0.4% in those who received DSE (p <.0001). These changes in weight were accompanied by reductions in A1c of 0.88% and 0.03% in the Nutrisystem-D and DSE groups, respectively (p <.0001), at 3 months. More than three-quarters (79%) of Nutrisystem-D participants met the ADArecommended target for A1c (< 7%). By comparison, less than half (47%) of those randomized to DSE met this benchmark. This study included a 3-month extension phase, in which all participants, regardless of initial group assignment, received the active intervention (including Nutrisystem-D). When participants who were originally in the control arm were switched to Nutrisystem-D after 3 months, their mean improvement in A1c was virtually identical to that of the original Nutrisystem-D arm. The within-group change in participants who were switched from DSE to Nutrisystem-D was statistically significant, p< These results shown here are derived from numbers reported in the publication.

3 It is important to note that Foster et al. (2009) analyzed outcomes on an intent-to-treat basis, rather than conducting a less stringent (less methodologically rigorous) completers analysis. Results among participants who complete a program are typically more impressive. Appropriate Nutrition for Type 2 Diabetes Prevention and Management The ADA also takes a position on the nature of the diet that is appropriate for weight loss in type 2 diabetic patients. Further quotes from the same 2010 position paper and a 2008 ADA position statement, Nutrition Recommendations and Interventions for Diabetes state the following: Monitoring carbohydrate intake, whether by carbohydrate counting, exchanges, or experience-based estimation, remains a key strategy in achieving glycemic control. (ADA 2010, pg. S24) Low-glycemic index foods that are rich in fiber and other important nutrients are to be encouraged. (ADA 2010, pg. S64) Saturated Fat intake should be less than 7% of total calories (ADA 2010, pg. S24) Reducing intake of trans fat lowers LDL cholesterol and increases HDL cholesterol; therefore intake of trans fat should be minimized (ADA 2010, pg. S24) Limit dietary cholesterol to <200mg/d. (ADA 2008, pg. S66) A reduced sodium intake (e.g. 2300mg/day) with a diet high in fruits, vegetables and low fat dairy products lowers blood pressure. (ADA 2008, pg. S70) Meal Replacements (liquid or solid prepackaged) provide a defined amount of energy, often as a formula or product. Use of meal replacements once or twice daily to replace a usual meal can result in significant weight loss. (ADA 2008, pg. S66) The nutritional daily averages for the Nutrisystem-D program are consistent with these guidelines. The program is far superior to the typical American diet, particularly in terms of saturated fat, trans fat, cholesterol, sodium, and fiber. Nutrisystem-D Daily Program Averages* Nutrisystem D Women s Plan Nutrisystem D Men s Plan Calories % from carbohydrate 53% 56% % from protein 24% 23% % from fat 23% 21% % from saturated fat 6% 5% Total Sugar (g) Fiber (g) Cholesterol (mg) Sodium (mg) *Nutrition averages are based on current program offerings combined with the nutrition averages of the most frequently used grocery foods in each category as reported in the USDA Food Database and based on customers self reported grocery food additions to the online food diary. These nutrition averages are comparable to the nutrient content of the programs used during the Foster et al. (2009) clinical trial. The Importance of Portion Control It is well recognized that the prevalence of obesity among US adults has doubled since the 1980s (Flegal et al., 2002; Hedley et al., 2004; Ogden et al., 2006; Flegal et al., 2010); this surge in prevalence followed a trend towards larger food portion sizes (Young & Nestle, 2002). Nutrisystem entrees are individually packaged in

4 appropriate serving sizes to support weight loss. As noted in the first section of this paper, studies suggest that providing some of the food for a weight loss attempt in the form of portion controlled packages improves short term weight loss outcomes. Conclusions: Expert opinion, as expressed in position statements from Federal health authorities (e.g., NHLBI) and the American Diabetes Association, reveals a scientific consensus as to the importance of weight loss for the prevention and management of type 2 diabetes. A reduced-calorie, low-fat, portion-controlled diet designed to produce gradual weight loss of 1-2 pounds per week is generally recommended for overweight or obese type 2 diabetics or prediabetics. The Nutrisystem-D program is consistent in design with the recommendations of these expert bodies. The actual home delivery of the elements of the diet that pose the greatest portion control challenges (entrees, snacks and desserts) is a key program feature that has been consistently associated with improved short term weight loss. The clinical data for Nutrisystem-D further support both the soundness of the national recommendations and the efficacy of the program. The Low Glycemic Index Diet for Type 2 Diabetes Management The optimal diet to follow for all people with type 2 diabetes to manage their disease has not yet been established. However, a statement issued by the American Diabetes Association in 2010 (ADA 2010) has identified several critical components of effective medical nutrition therapy. They include: slow, moderate weight loss (at least 5% of initial body weight); a nutrient-rich diet low in both saturated and trans fats; and close monitoring of total carbohydrate consumption (by means of carbohydrate counting, food exchanges, or individualized estimations of consumption). In addition, the ADA states: For individuals with diabetes, use of the glycemic index and glycemic load may provide a modest additional benefit for glycemic control over that observed when total carbohydrate is considered alone. (ADA 2010, pg. S24) Glycemic Index and Glycemic Load Defined The term glycemic index was first used in a 1981 published manuscript by Jenkins et al.; the peer-reviewed literature now contains hundreds of research papers and at least 69 review articles on the topic (for two recent reviews, see Brand Miller et al, 2009, and Esfahani et al., 2009). The glycemic index (GI) is an empirically derived measure of blood glucose response to carbohydrate intake. To calculate GI, the incremental area under the glucose response curve following ingestion of a fixed, standard amount of carbohydrate in a particular food is compared to the incremental area under the glucose response curve following consumption of the same amount of carbohydrate from a control food (typically a glucose solution or white bread). An additional tool, the glycemic load (GL), has recently been developed to determine the glycemic response to the total carbohydrate load from consuming a particular food or diet. Foods referred to as low glycemic are digested slowly, causing a gradual and prolonged increase in postprandial blood glucose levels. In contrast, high glycemic carbohydrate foods are rapidly digested, causing an immediate and strong glycemic response. As a result, calorie-for-calorie, regularly consumed high glycemic index meals in people with type 2 diabetes can result in higher blood glucose and insulin levels, in addition to higher glycosylated hemoglobin levels, compared to results from low glycemic meal consumption (Ludwig, 2003). A recent meta-analysis found that reductions in A1c were 0.5 to 0.9% greater among patients with diabetes who received low GI diets, compared with higher GI alternatives (Thomas & Elliott, 2009). While the science supports recommending a low glycemic index diet for glycemic control and weight loss in people with type 2 diabetes, adherence to this dietary approach may be challenging for patients. The primary dietary need for everyone with type 2 diabetes is tight control of the total amount of carbohydrate consumed (ADA 2010, pg S24). Some patients may become overwhelmed if they simultaneously try to master both the amount and type of carbohydrates in their diets. In addition, the glycemic index of a food is affected by many factors, including macronutrient content, food processing, and even food ripeness. It is not possible to determine the glycemic index of a food by reading a nutrition facts panel. So, while it is possible to teach adherence to a low GI diet, use of the Nutrisystem-D program greatly reduces the guesswork and complexity

5 of food selection and meal planning. Entrées in the Nutrisystem programs are tested by an independent laboratory for glycemic index, to ensure that the overall program is consistent with the GI profile that has been shown to be beneficial for glycemic control, among other benefits. The following graph represents a typical change in blood glucose over two hours when subjects are fed either a low glycemic index Nutrisystem entrée or an equivalent carbohydrate load from high glycemic index white bread. The data suggest slower carbohydrate digestion and absorption with the low glycemic index entrée, resulting in a significantly lower blood glucose concentration. Diets comprised primarily of low glycemic index foods have been associated with better glycemic control, satiety, and body weight management, compared to high glycemic index diets (Brand Miller et al., 2009; Esfahani et al., 2009; Thomas & Elliott, 2009). Conclusions: Managing calorie and carbohydrate intake is the primary intervention to produce weight loss and improve glycemic control in patients with type 2 diabetes. Research suggests combining this approach with a low glycemic diet further supports weight management and glycemic control in patients with type 2 diabetes. The Nutrisystem Program is evaluated to ensure the program is consistent with the GI profile that has been shown to be beneficial for glycemic control, among other outcomes. Efficacy of Behavior Therapy Techniques The NHLBI s Clinical Guidelines for the Treatment of Obesity recommend that dietary and physical activity recommendations be packaged with a behavioral intervention (National Heart, Lung and Blood Institute Obesity Education Initiative, 1998). This combined treatment is often referred to as a lifestyle modification program. The key difference between a diet (as commonly defined by patients) and a lifestyle modification program is the intent of the latter to implement reasonable changes that can be sustained indefinitely to promote health (Fabricatore & Wadden, 2003). Behavior therapy (alternatively referred to as cognitivebehavioral therapy in this context) refers to a set of principles and strategies that help patients adhere to their diet and physical activity goals. Such strategies include problem solving, stimulus control, cognitive restructuring, stress management and seeking social support (Fabricatore, 2003; National Heart, Lung and Blood Institute Obesity Education Initiative, 1998). Chief among these strategies, however, is self-monitoring. Self-Monitoring Regular self-monitoring of food intake, physical activity, and body weight has become a critical component of behavior therapy for weight management, as several studies have found more favorable weight loss

6 outcomes among those who self-monitor more consistently. (Baker & Kirschenbaum, 1993; Foreyt & Goodrick, 1994; Foreyt & Poston, 1998). Although food intake is the primary target of self-monitoring, researchers also have investigated the effects of self-monitoring physical activity. In a group of 40 obese, sedentary men and women who were participating in a six-month weight loss program, 43% achieved a consistent level of self-monitoring (Carels, 2005). Those who monitored their activity consistently completed twice as much physical activity each week and lost twice as much weight as those who monitored their activity inconsistently. Body weight also appears to be an important target of self-monitoring. Research on members of the National Weight Control Registry (NWCR), a database of successful dieters (i.e., individuals who have lost at least 30 lb and maintained that reduction for at least 1 year), has identified several behaviors that are characteristic of successful weight losers. One of the earliest studies conducted in the NWCR found that 44% of participants weighed themselves at least once per day and an additional 31% weighed themselves once per week (Klem, 1997). This finding was recently replicated in a larger NWCR sample (Butryn, 2007). NWCR participants reported using self-weighing as an opportunity for positive reinforcement when changes in behavior correspond to weight loss or avoidance of weight gain. Despite the evidence supporting the role of self-monitoring in meeting weight loss goals, achieving a consistent level of self-monitoring can be a significant challenge. Providing individualized, convenient and motivational tools to patients that support self-monitoring activity may enhance self-monitoring adherence. Conclusions: Self-monitoring of food intake, physical activity and weight can help increase selfawareness of target behaviors, illustrate progress towards goals, and serve as a warning system for problems that arise. Consistent adherence to self-monitoring practice at least 75% of the time increases the likelihood of weight loss and weight management success. More than half of people find it difficult to consistently self-monitor. The Nutrisystem Program provides access to both webbased and paper-based self-monitoring tools that have been designed to be motivational and customizable to members individual goals in order to promote adherence to targeted self-monitoring behaviors. Evaluating the Efficacy of Telephone Counseling and Web-Based Behavior Therapy Behavior therapy is typically delivered in individual or group counseling sessions that are held on a weekly to monthly basis. These face to face sessions include a review of patient progress and discussion of methods and strategies to help patients adhere to recommendations for energy intake and physical activity. However, barriers such as program availability, patient proximity, transportation, and time constraints can limit program access and adherence. Current information and communication technologies, specifically web, and telephone technologies have the potential to overcome these barriers and numerous studies have evaluated the efficacy of the various alternative channels (Wadden et al., 2007). A randomized controlled trial compared the efficacy of an in-person lifestyle modification program (consisting of weekly on-site group sessions) to an internet-based program (consisting of weekly chat room sessions and a variety of web based self-monitoring tools) and a hybrid program (consisting of the internet-based treatment plus monthly in-person group sessions; Harvey-Berino, 2010). The in-person group lost significantly more weight than the internet and hybrid groups (8 kg vs. 5.5 kg and 6 kg, respectively) at 6 months. The largest difference among study groups was perceived social support which was significantly higher for the in-person group. This suggests that social support may be one mechanism by which the in-person format produced superior weight loss. Despite lower mean weight reductions in the internet and hybrid groups, clinically meaningful weight losses were common; 38% of Internet participants and 44% of hybrid participants lost at least 7% of their initial weight. Telephone counseling may also be an alternative to face-to-face interventions. In a randomized trial, participants who received on-site counseling lost significantly more weight (median: 13.7%) at 3 months than those who received telephone counseling (median: 10.4%), but there were no differences between groups at 6

7 months (medians: 12.6% and 13.0% for the on-site and telephone counseling groups, respectively; Donnelly, 2007). Attrition was lower in the telephone group (26%) than in the on-site group (31%). With regard to weight maintenance, a recent randomized controlled study compared two weight loss maintenance interventions (a personal contact and an interactive technology intervention) with a self-directed control group over a period of 30 months (Svetkey, 2008). Both the personal contact and interactive technology intervention encouraged regular self-monitoring of weight, physical activity and caloric intake. The interactive technology group consisted of unlimited access to a host of online tools, and the personal contact group consisted of monthly minute telephone sessions. Randomization into these maintenance programs occurred after a mean weight loss of 8.5 kg over 6 months. The primary outcome observed was change in weight since randomization into maintenance programs. At the end of the study, all groups had regained weight (means of 5.5 kg in self-directed group, 5.2 kg in interactive technology group, and 4.0 kg in personal contact group), however at 24 months both the interactive technology group and the personal contact group had gained significantly less weight (p values = and <0.001 respectively) than the self-directed group, and at 30 months the personal contact group had regained significantly less weight (p value =.001) than the self-directed group. Conclusions: a face-to-face clinic-based approach is considered the gold standard for the delivery of an effective lifestyle modification program; however alternative delivery channels can produce clinically significant weight management results that offer solutions for common barriers to clinic based program participation. The Nutrisystem program offers multiple access channels for receiving behavioral therapy support which include: telephone counseling, online Live Chat, interactive behavior modification workbooks, and online classes with a registered dietitian. The Role of Physical Activity in Weight Management and Diabetes Prevention Despite significant benefits of physical activity for reducing risks of heart disease, cancer, diabetes, bone and joint disease, and mortality (CDC, 1996), physical activity appears to play a relatively minor role in the induction of weight loss in obese persons. Adding physical activity to a dietary intervention only modestly increases weight loss over diet alone (Catenacci, 2007). At high doses, physical activity can enhance weight loss, but such levels are difficult for many individuals especially those who are overweight or obese to achieve. Thus, dietary restriction is the primary intervention for inducing calorie deficit. Physical activity, however, appears critical to the maintenance of a weight loss. A review of 6 randomized controlled trials that compared diet plus exercise interventions with diet alone, all with follow up greater than 1 year after initial intervention, showed that the total weight reduction at the end of follow-up was 20% greater in programs that included diet and exercise, compared with diet alone (Curioni, 2005). Conclusions: Physical activity is a necessary component of a lifestyle modification program as current research suggests that engaging in physical activity can improve weight loss and weight management success. Additionally, achieving a 7 percent loss of body weight and 150 minutes of moderate-intensity physical activity per week can reduce the risk of developing diabetes by 58% in those who are at high risk. Nutrisystem provides downloadable progressive workout plans, aerobic and strength training exercise DVDs, tracking tools to monitor progress towards physical activity goals and a library of resources that support members in achieving a level of physical activity that is correlated with improvements in health status. SUMMARY A scientific consensus supports the importance of weight loss for the prevention and management of type 2 diabetes. A reduced-calorie, low-fat, portion-controlled diet designed to produce gradual weight loss of 1-2 pounds per week is generally recommended for overweight or obese type 2 diabetics or pre-diabetics. Designing such a diet to also be low glycemic index is generally thought to further support weight management and glycemic control. The Nutrisystem-D meal plan is consistent in design with these recommendations. The actual home delivery of the elements of the diet that pose the greatest portion-control challenges (entrees,

8 snacks and desserts) is a key program feature. The emphasis on portion-control is consistent with an approach that has repeatedly been shown to be associated with improved short term weight loss. In addition, the Nutrisystem-D program provides self-monitoring tools, physical activity programs, and online/telephonic counseling consistent with recommendations for diabetes prevention and management. References American Diabetes Association Standards of Medical Care in Diabetes. Diabetes Care. 33 Suppl:S11- S61. American Diabetes Association Nutrition Recommendations and Interventions for Diabetes: A Position of the American Diabetes Association. Diabetes Care. 31 Suppl:S61-S78. Baker R and Kirschenbaum D Self-monitoring may be necessary for successful weight control. Behavior Therapy 24: Boutelle K and Kirschenbaum D Further support for consistent self-monitoring as a vital component of successful weight control. Obesity Research 6: Brand-Miller J, McMillan-Price J, Steinbeck K, Caterson I Dietary Glycemic Index: Health implications. J Am Coll Nutr. 28 Suppl:446S-449S. Butryn M, Phelan S, Hill J, Wing R Consistent Self-monitoring of Weight: A Key Component of Successful Weight Loss Maintenance OBESITY 15(12): Carels R et al The Relationship Between Self Monitoring, Outcome Expectancies, Difficulties with Eating and Exercise, and Physical Activity and Weight Loss Treatment Outcomes. Annals of Behavioral Medicine 30(3): Catenacci V, Wyatt H The Role of Physical Activity in Producing and Maintaining Weight Loss. Nat Clin Pract Endocrinol Metab CME 3(7): Center for Disease Control and Prevention Physical Activity and Health. A Report of the Surgeon General: Cheskin et al Efficacy of meal replacements versus a standard food-based diet for weight loss in type 2 diabetes: a controlled clinical trial. The Diabetes Educator 34: Curiono CC, Lourenco PM Long-Term Weight Loss After Diet and Exercise: A Systematic Review. Int J Obes 29: Ditschuneit et al.,1999. Metabolic and weight-loss effects of a long-term dietary intervention in obese patients. Am J Clin Nutr 69(2): Donnelly JE Comparison of a Phone vs. Clinic Approach to Achieve 10% Weight Loss. International Journal of Obesity 31: Esfahani A, Wong JM, Mirrahimi A, Srichaikul K, Jenkins DJ, Kendall CW The glycemic index: physiological significance. J Am Coll Nutr. 28 Suppl: 439S-445S. Espeland M et al Reduction in Weight and Cardiovascular Disease Risk Factores in Individuals with Type 2 Diabetes: One- Year Results of the Look AHEAD Trial. Diabetes Care 30(6): Esfahani A, Wong JM, Mirrahimi A, Srichaikul K, Jenkins DJ, Kendall CW The glycemic index: physiological significance. J Am Coll Nutr Aug;28 Suppl:439S-445S. Fabricatore A, Wadden T Treatment of Obesity: An Overview. Clinical Diabetes 21(2): 67-72

9 Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in Obesity Among US Adults, JAMA 2002;288: Flegal KM, Carroll MD, Ogden CI, Curtin LR. Prevalence and trends in obesity among US adults, JAMA 2010;303: Foreyt JP, Goodrick GK Attributes of Successful Approaches to Weight Loss and Control. Applied and Preventative Psychology 3: Foreyt JP, Poston WSC The Role of the Behavioral Counselor in Obesity Treatment. Journal of the American Dietetic Association, 98(10; Supplement 2): Foster et al The Effects of a Commercially Available Weight Loss Program Among Obese Patients with Type 2 Diabetes: A Randomized Study. PostGraduate Medicine 121(5). Hannum et al Use of Portion Controlled Entrees Enhances Weight Loss in Women. Obesity Reseach 12(3). Hannum et al Use of packaged entrees as part of a weight-loss diet in overweight men: an 8-week randomized clinical trial. Diab Obes Metab 8: Harvey-Berino J, West D, Krukowski R, Prewitt E, VanBiervliet A, Ashikaga T, Skelly J Internet delivered behavioral obesity treatment. Preventive Medicine. 51; Hedley AA, Ogden CL, Johnson CL, Carroll MD, Curtin LR, Flegal KM Prevalence of overweight and obesity among US children, adolescents, and adults, JAMA;291: Heymsfield et al Weight Management Using a Meal Replacement Strategy: Meta and Pooling Analysis from Six Studies. Int J Obs 27: Jenkins DJ, Wolever TM, Taylor RH, Barker H, Fielden H, Baldwin JM, Bowling AC, Newman HC, Jenkins AL, Goff DV Glycemic index of foods: a physiological basis for carbohydrate exchange. Am J Clin Nutr. 34(3): Kanfer FH Self-monitoring: Methodological limitations and clinical applications. Journal of Consulting and Clinical Psychology 35: Kirschenbaum DS Treating adult obesity in 1988: Evolution of a modern program. The Behavior Therapist, 11:3-6. Kirschenbaum DS Elements of effective weight control programs: Implications for exercise and sport psychology. Journal of Applied Sport Psychology 4: Klem ML, Wing RR, McGuire MT, Seagle HM, Hill JO A descriptive study of individuals successful at long-term maintenance of substantial weight loss. Am J Clin Nutr, 66: Ludwig, DS The glycemic index: physiological mechanisms relating to obesity, diabetes, and cardiovascular disease. JAMA 287(18): National Heart, Lung and Blood Institute Obesity Education Initiative Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. US Dept of Health and Human Services. NIH Publication No National Heart, Lung and Blood Institute. Manage Diabetes: Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM Prevalence of overweight and obesity in the United States, JAMA;295:

10 Svetkey LP, Stevens VJ, Brantley PJ, Appel LJ, Hollis JF, Loria CM, et al Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial. JAMA, 299: Thomas D, and Elliott EJ Low glvcaemic index, or low glycaemic load, diets for diabetes mellitus. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD DOI = / CD pub2. Wadden et al Lifestyle modification for the management of obesity. Gastroenterology 132: Yip IAN, Vay Liang W, Go, Deshields S, Saltsman P, Bellman M, Thames G, Murray S, Want HJ, Elashoff R, Heber D. Liquid meal replacements and glycemic control in obese type 2 diabetes patients. Obes Res. 2001;9:341S 347S. Young LR & Nestle M The contribution of expanding portion sizes to the US obesity epidemic. American Journal of Public Health 92(2):