Behavioral Therapy for Weight Loss

DRAFT

A global public health issue plaguing society is excess weight; an estimated 1.46 billion adults are overweight and an estimate of 205 million men and 297 million women older than 20 years old are obese in the world (Finucane et al., 2011). Between 1980 and 2008, the body mass index (BMI) increased by 0.4 to 0.5 per decade for both men and women (Finucane et al., 2011). According to the World Health Organization (2009), the rising BMI in the population means that there is an increased risk factor for mortality and morbidity from numerous chronic diseases: type 2 diabetes, cardiovascular disease, several cancers, and more. If individuals lose a modest amount of weight, then they can see a decrease in disease risk factors and an improvement in quality of life (Klein et al., 2004). As such, identifying effective interventions for weight loss can ameliorate the public health epidemic. The cornerstone in the management of obesity is therapeutic lifestyle interventions that target restricting calories and increasing physical activity (PA). Behavioral therapy (BT) is an intervention can help individuals develop a set of skills to achieve a healthier weight (Jacob & Isaac, 2012; Stuart, 1967).

Assumptions of Behavioral Therapy (BT)

There are two main assumptions that underlie the use of BT for managing obesity (Jacob & Isaac, 2012; Stuart, 1967). BT for obesity originated from the idea that obesity was due to maladaptive eating and exercise habits. Thus, these maladaptive behaviors can be modified with specific interventions that can lead to weight loss. From these assumptions, principles that originated from classical and operant conditioning are applied to help obese individuals learn new behaviors that reduce calorie intake and/or increase PA (Jacob & Isaac, 2012; Stuart, 1967). Recently, researchers have acknowledged that looking solely at behavior is too simplistic because there are other factors that have been shown to impact weight: genetic, metabolic and hormonal influences (Snyder et al., 2004; Comuzzie, 2001). These factors most likely predispose individuals to obesity and/or set the range of possible weights that an individual can achieve (Foster, Makris, & Bailer, 2005). Therefore, BT can be utilized to help individuals learn and develop skills to achieve a healthier weight range than they currently have.

BT predominantly uses classical conditioning for weight management. As applied to eating behaviors, the theory of classical conditioning asserts that eating is often prompted by antecedent events (cues) and that become strongly associated with food consumption (Stuart, 1967). Therefore, BT helps patients to identify cues that trigger inappropriate eating and activity, while also teaching new responses to these triggers (Wing, 2002). It is also important to reinforce (reward) the adoption of adaptive behaviors. Since 1974, cognitive therapy has augmented behavioral treatment for obesity (Foster et al., 2005; Butryn, Webb, & Wadden, 2011). The rationale for adding a cognitive component is that thoughts directly impact feelings and behaviors, with negative thoughts usually associated with negative outcomes (Beck, 1976).  Adding cognitive therapy to BT for weight loss helps patients to learn to set realistic goals for weight and behavioral change, to evaluate their progress realistically, and to correct negative thoughts that may arise during treatment (Foster, 2002).

Structure of BT

The structure of treatment usually consists of BT on a weekly basis for approximately four to six months (Butryn et al., 2011). Treatment may continue for an additional 20 to 26 weeks with bi-weekly sessions to focus on building weight loss maintenance skills. Treatment is usually provided in groups of 10 to 15 individuals and lasts approximately 60 to 90 minutes. Groups are facilitated by group leaders who hold a degree in nutrition, psychology, or a related field (Butryn et al., 2011).

There is some research to suggest that group therapy is more effective than individual therapy. Renhilian and colleagues (2011) conducted a randomized controlled trial with 75 obese adults that were assigned to either individual or group BT. Group BT found participants lose significantly more weight than individual BT, even if individual’s preference was initially individual BT (Renhilian et al., 2011). These findings are noteworthy because group therapy has some advantages over individual therapy, like cost-effectiveness and providing a combination of empathy, social support, and healthy competition (Wadden & Foster, 2000). Nonetheless, individuals can choose to receive BT in clinical settings, self-help groups, commercial weight loss programs, or internet based programs (Jacob & Isaac, 2012).

Typical sessions start with a private measurement of weight (Butryn et al., 2011). At every meeting, patients share with the group how successful they were in meeting their behavioral goals and patients report that they appreciate the accountability to the group when they report their progress. However, the amount of weight change is usually not shared with the group. Following, a new weight management skill is taught in each session that is based on a structured curriculum. Some skills that are taught include making healthy selections when eating out at restaurants, portion control, and obtaining social support for accomplishing goals (Butryn et al., 2011).

There are several guidelines that can improve patient’s adherence to the behaviors that are necessary for effective weight loss (Foster et al., 2005). The therapist should provide the patient with a rationale for changing their behavior and ensure that the patient understands the rationale. Additionally, it is critical to establish a specific plan that describes the behavior in concrete and specific terms. The patient should also identify their facilitators and barriers to success from the beginning to end of treatment. Finally, the patient must make a written record of the plan and key steps in its implementation (Foster et al., 2005).

Principles and Common Components of BT

Goal directed. BT includes concrete behavioral goals that can be easily measured (Wadden & Foster, 2000). These objective goals make it easier to assess patients’ progress (Butryn et al., 2011). Each patient has a target for average daily calorie intake, weekly minutes of PA, and number of days that a food record needs to be completed in a week. Additionally, patients are encouraged to set additional goals for themselves that will result in losing or maintaining weight. When patients are setting their own goals, they are advised to operationalize their behavioral goal and consider how, when, and where the behavior will be completed (Butryn et al., 2011). For example, a patient may want to drink more water, which can be clearly defined by stating that they will drink at least 16 oz of water at lunch and dinner, five days a week.

Process oriented. Treatment is process oriented to help people to decide what to change and how to change (Foster, 2002). Once the goals are established, patients are asked to examine factors that will both facilitate and hinder achieving their goals. If a desired behavior is not implemented, then problem-solving skills are used to identify new strategies to overcome barriers to achieve their goals (Foster, 2002).

Small changes vs. larger changes. BT also focuses on small changes, as opposed to large ones. This is based on the learning principles of successive approximation, where incremental steps are taken to achieve more distant goals (Foster et al., 2005). Making small changes positively reinforces patients to continue with their goals; setting large goals may be too daunting and cause people to drop-out of treatment (Foster et al., 2005).

Self-monitoring. Patients are advised to systematically record their target behaviors (Butryn et al., 2011). Self-monitoring provides regular feedback about target behaviors and is strongly associated with weight loss success. Researchers have found that patients who monitor their eating and weight will most consistently have the greatest success in losing weight (Butryn, Phelan, Hill, & Wing, 2007; Wadden et al., 2005). Even in a placebo versus pharmaceutical agent trial, individuals who successfully maintained a record of their food intake lost twice as much weight than those who did not (Wadden et al., 2005). As such, patients keep a weekly record of all food and beverages that they consume and calculate their daily calorie intake, and possibly other macro nutrients (Butryn et al., 2011). The food record is vital in the early phase of treatment to identify eating patterns that can be modified to ultimately reduce calorie intake. Patients may also be asked to monitor other factors that are related to eating behaviors like their hunger level, mood, or location when eating. Additionally, patients are asked to record the number of minutes of PA or daily number of steps (Butryn et al., 2011). Self-monitoring is one of the hallmarks of BT.

Stimulus control. The behavioral change process uses a variety of problem-solving tools that are founded on stimulus control principles. These are used to change both the internal and external cues that are associated with targeted eating and activity behaviors (Foster, 2006). As such, patients are taught to change their immediate environment, home or workplace, to facilitate their behavioral change as opposed to thwarting it (Butryn et al., 2011). For example, reducing exposure to tempting high-calorie foods for the patient should reduce the consumption of that type of food and lower calorie intake. To increase the patient’s likelihood of PA, it may be recommended to place sneakers and workout clothing next to one’s bed as a reminder to be physically active. The behavior chain is a common tool used in treatment, as it examines the cues and events that lead to maladaptive eating patterns (Foster et al., 2005). Implementing the behavior chain can facilitate in the identification of areas that changing a behavior can possibly “break” the chain of events and prevent an overeating episode from occurring (Foster et al., 2005).

Slower eating. Individuals are advised to eat at a slower rate to allow their body to signal that they are full (Jacob & Isaac, 2012). Common techniques to slow eating include concentrating on tastes, pausing between meals, and drinking water in between meals (Jacob & Isaac, 2012).

Goal setting. Patients are encouraged to set realistic goals that are framed to lose weight in terms of weight loss per week or month (Volp et al., 2008). The group leaders typically advise patients that they should expect 0.5 to 1.0 kg of weight loss per week and to ultimately lose 10% of their initial body weight at the end of treatment (Butryn et al., 2011).

Behavioral contracting. Reinforcement of successful outcomes and rewarding good behaviors is advantageous to treatment. These rewards can be in the form of small tokens or even financial incentives (Jacob & Isaac, 2012). Volpp and colleagues (2008) conducted a 16-week randomized control trial with 57 participants, where individuals were finically incentivized to make their goals. This led to an average weight loss of 6 kg for the financially incentivized group and only 1.77 kg for the control group (Volpp et al., 2008).

Education. Nutritional education is an important component of BT. Thus, it is not surprising that a structured meal plan created for an individual collaboratively with a dietitian results in a greater weight loss than those not provided with these services (Wing & Phelan, 2005).

Increasing physical activity (PA). Increasing individual’s PA is also promoted in BT. There have been numerous studies to suggest that self-monitoring and increasing PA are consistently associated with better outcomes for both short and long term outcomes (Jacob & Isaac, 2012; Wing & Phelan, 2005).

Social support. When individuals participate in BT, it is beneficial to have social support to sustain results. Thus, it is advised to enhance the patient’s social support by including spouses and family members in treatment (Jacob & Isaac, 2012). One meta-analysis found that including family members in the therapy process led to an additional 3 kg of weight loss compared to programs that did not include family members (Avenell et al., 2008).

Other less proven components. There are other components of BT that are utilized, but they have not been as critical for the success of BT for weight loss (Jacob & Isaac, 2012). These include cognitive restructuring and adopting positive outlooks, problem solving, assertiveness training to say no, and stress reduction (Jacob & Isaac, 2012).

Effectiveness of Behavioral Treatment & Improving Outcomes

Participants who undergo BT lose approximately 8-10 kg of weight, which is equal to 8-10% of their initial body weight (Wadden, Butryn, & Wilson, 2007). Furthermore, approximately 80% of participants who start treatment will complete it. BT yields favorable results according to the National Institute of Health, which states the criteria of a successful intervention is a 5% to 10% reduction in initial weight. In the past 30 years, weight loss has more than doubled as the treatment duration has tripled (Wadden et al., 2007). The overall rate of weight loss has remained consisted at about 0.4 to 0.5 kg per week (Butryn et al., 2011). Behavioral treatment for weight loss can be augmented to help individuals lose more weight.

Food Provisions. Augmenting BT with food provisions was studied by randomly assigning 202 participants to no treatment, standard BT (SBT), SBT + food provisions, SBT + incentive, or SBT + food provision and incentive (Jeffery et al., 1993). The researchers found that food provisions significantly enhanced weight loss compared to SBT at 6 months (-10.1 vs. -7.7kg), 12 months (-9.1 vs. -4.5kg), and 18 months (-6.4 vs. -4.1kg). Additionally, food provisions enhanced attendance, completion of food records, quality of diet, and nutrition knowledge (Jeffery et al., 1993). Wing et al (1996) wanted to determine if food provision itself or limited dietary decision making impacted the weight loss outcome. A total of 163 overweight women were randomly assigned to a group: (1) SBT with weekly meetings for six months, (2) SBT plus structured meal plans and grocery list, (3) SBT plus meal plans and food provisions, or (4) SBT plus meal plans with free food provisions. The researchers found that the SBT group lost significantly less weight than all other groups. Importantly, there was no significant difference between groups 2-4, which suggests that the component of food provision that is critical for weight loss is the provision of a highly-structured meal plan and grocery list (Wing et al., 1996). Taken together, these studies suggest that providing structured meal plans and grocery lists to patients can improve their outcome in a behavioral treatment program.

Meal Replacements. Replacing meals shows similar findings as adding food provisions to BT.The research suggests that replacing two of three meals, that are portion-controlled, results in a greater weight loss than self-selected diets (Foster et al., 2005). A meta-analysis found that individuals who had meal replacements lost approximately 7-8% of their body weight, compared to the 3-7% for individuals on a standard self-selected diet at one year (Heymsfield, van Mierlo, van der Knaap, Heo, & Frier, 2003). These findings indicate that increasing the structure in what a patient consumes could improve weight loss results.

Pharmacotherapy. Weight loss outcomes can be enhanced by coupling behavioral and pharmacotherapy approaches. Behavioral treatment is thought to modify the external environment, while pharmacologic approaches modify the internal environment (Foster et al., 2005). One study randomly assigned 53 women to either sibutramine alone, sibutramine + lifestyle modifications that is aimed to reduce calorie intake, or sibutramine + behavior modification with meal replacements (Wadden, Berkowitz, Sarwer, Prus-Wisniewski, & Steinberg, 2001). All the patients received the same dosage of sibutramine, so the study focused on assessing the dose response of increasing behavioral treatment. At 6 months, the group with the most behavioral modification lost the most weight compared to drug alone (-17.7% vs. -5.8% of initial body weight), and they maintained the loss at 1 year (-16.5% vs. -4.1%). This study suggests that increasing the amount of BT will increase the short term and long term weight loss of patients (Wadden et al., 2001).

Motivational Interviewing (MI). It may be beneficial to tailor programs based on participant’s baseline characteristics, like motivation. Motivational interviewing is one popular technique that can be used to increase an individual’s intrinsic motivation to change. One study assessed the outcomes of two internet behavioral weight loss interventions: standard group and motivation-enhanced group that included MI (Webber, Gabriele, Tate, & Dignan, 2010). The researchers found that in participants with high levels of baseline controlled motivation for weight loss, MI produced significantly greater weight loss than a standard behavioral weight loss intervention (Webber at al., 2010). Carels and colleagues (2007) investigated ways to improve behavioral weight loss program (BWLP) treatment outcomes by comparing BWLP to BWLP + MI. The researchers found that participants in the BWLP +MI group lost significantly more weight and engaged in greater weekly exercise than the BWLP group. These results suggest that MI may be advantageous to supplement treatment for individuals experiencing weight loss difficulties in a BWLP (Carels et al., 2007). However, MI may not be suitable to supplement treatment for all populations. Befort and colleagues (2008) found that African American women benefited from a BWLP, as they lost a significant amount of weight. However, the BWLP + MI did not significantly differ from the BWLP + health education (attention control) group (Befort et al., 2008). This suggests that MI may not be effective in improving outcomes for all groups participating in a BWLP.

Diet or PA Intervention vs. Combined

The inclusion of diet and/or PA in BT for weight loss is an important consideration to determine what is essential for weight loss, as opposed to something that is inconsequential. Combined programs have compared SBT to diet-only interventions (Bertz et al., 2012; Skender et al., 1996; Vissers et al., 2010). Pooled results have shown that mean weight loss at 3 to 6 months did not differ significantly between combined programs or those that included diet only, where the pooled mean difference was -0.62 kg (Johns, Hartmann-Boyce, Jebb, Aveyard, & Behavioural Weight Management Review Group, 2014). However, at 12 months pooled results showed that mean weight loss was significantly higher in combined programs, as opposed to ones that focused solely on diet only: mean difference =-1.72 kg (Johns et al., 2014). Combined programs have also been compared to PA only interventions (Bertz et al., 2012; Rejeski et al., 2011; Skender et al., 1996). The pooled results showed that weight loss at 3 to 6 months was significantly higher in combined programs than those that only had PA (Johns et al., 2014).

Taken together, the results suggest that weight loss is similar in the short-term for diet-only interventions and combined BWMPs, but for the long-term, weight-loss is greatest when combining PA and diet interventions (Johns et al., 2014).  Programs that only utilize PA are less effective than combined programs, and this is true for both short and long term interventions. It seems that programs that combine PA and diet lead to changes in either behavior that are at least as large as programs that focus solely on just diet or PA. The results indirectly suggest that the addition of diet to a PA intervention is more advantageous than adding PA to a dietary program. This eludes to the notion that dietary changes are a critical component on initiating weight-loss. It also seems that PA can be more beneficial for the maintenance of weight loss, which is consistent with other studies (Johns et al., 2014; Fogelholm & Kukkonen-Harjula, 2000; Jeffery et al., 2003; Tate et al., 2007; Wadden et al., 1998).  Overall, it seems that combined programs on average are better than diet or PA only intervention, but combined programs are not always more beneficial depending on the duration of treatment (Johns et al., 2014)

Strategies Improving Weight Loss Maintenance

Weight loss usually reaches a peak at 6 months and then weight will usually be regained if therapy has ceased. After treatment has terminated, patients will typically regain about one-third of their lost weight within a year and return to their original weight within five years (Wadden et al., 2007; Wing, 2002). Unfortunately, individuals who succeed at losing weight in behavioral treatment will face barriers to maintain their weight loss, like having large portion sizes and social pressure to eat (Drewnowski & Rolls, 2005). Furthermore, metabolic responses to weight loss, biological preferences for higher calorie food, and conservation of energy may make it difficult to sustain weight loss (Rosenbaum, Hirsch, Gallagher, & Leibel, 2008). As such, there appears to be internal and external barriers that may make it difficult for patients to maintain their weight loss, so extra vigilance must be taken to maintain appropriate eating and PA behaviors.

Long term patient-provider contact. Long term patient-provider contact following initial weight loss is viewed as the most successful method of preventing weight regain (Butryn et al., 2011). Perri et al (1988) found that every-other week maintenance sessions are associated with excellent long-term weight loss and that these participants could maintain 13.0 kg of their 13.2 kg end of treatment weight loss, which was higher than those who did not receive extra treatment (5.7 kg of 10.8 kg loss). Furthermore, patients who received long-term treatment that lasted approximately 54 weeks maintained 10.3 kg of their initial 10.7 kg weight loss (Perri & Corsica, 2002). Monthly, on-site, group counseling sessions were shown to be more effective in preventing weight regain over 18 months of intervention when compared to an education-control group or an internet-based intervention (2.5,4.9, 4.7 kg weight regain of 19 kg initial weight loss) (Wing, Tate, Gorin, Raynor, & Fava, 2006). Additionally, the researchers found that participants in all three groups who monitored their weight at least once a week were the most successful in maintaining their weight loss (Wing et al., 2006). Thus, it appears that weight loss maintenance sessions provide participants with the support and motivation to continue to practice weight control behaviors like engaging in PA, eating a low calorie and/or low-fat diet, monitoring body weight, and recording food intake occasionally (Perri & Corsica, 2002).

Internet and telephone. Even though longer treatment has shown to help patients maintain their weight loss, it may be difficult for participants to continue attending therapy. As such, long-term contact via internet and telephone has been studied in its ability to facilitate extended contact with the treatment team to promote weight loss maintenance. The benefits of this approach are that they can reach more people, improve cost-effectiveness, and allow for greater flexibility for the participant (Butryn et al., 2011). There are conflicting results on the effectiveness of implementing internet maintenance treatment options, where some research has shown that internet performs poorer than face-to-face (Harvey-Berino et al., 2002), an interactive internet-based intervention performed better than face-to face (Svetkey et al., 2008), and internet and face-to-face were found to be equally effective (Harvey-Berino, Pintauro, Buzzell, & Gold, 2004). These studies suggest that more research is warranted in this area to determine if the internet is a viable option to help patients maintain their weight loss and the best ways to implement use of the internet to facilitate weight loss maintenance. On the other hand, twice monthly counseling sessions that were given over the phone for 15-20 minute sessions has been shown to be as effective as on-site group counseling in maintaining weight loss (Perri et al., 2008). As such, telephone counseling is a possible cost-effective option for maintenance of weight loss.

PA. High levels of PA may also help patients maintain their weight loss. A systematic review found that individuals who engage in PA experience less weight regain than those individuals who did not, while individuals who engaged in the highest level of PA experienced less regain compared to those who engaged in less PA (Fogelholm & Kukkonen-Harjula, 2000). It is recommended that individuals participate in 30 to 60 minutes of activity because it is associated with weight loss maintenance. One research team found that a 1 year program of supervised exercise training resulted in similar weight loss maintenance than a program of diet alone, and participants who stated that they exercised regularly during follow-up had less weight regain than those individuals who did not exercise (Wadden, Vogt, Foster, & Anderson, 1998). High level of PA has been shown to result in significantly greater weight loss maintenance at 18 months than those told to complete a lower level of PA (Jeffery, Wing, Sherwood, & Tate, 2003; Tate, Jeffery, Sherwood, & Wing, 2007). However, many participants were unable to sustain this high level of PA after the 18-month period, so at 30 month follow up there were no group differences (Tate et al., 2007). Those individuals that could sustain high levels of PA maintained significantly larger weight loss than those participants who engaged in lower levels of PA. Taken together, the research suggests that adults who want to sustain their weight loss should engage in at least 60 minutes per day of brisk walking (Tate et al., 2007).

Pharmacotherapy. The final approach to sustaining weight loss is with long-term use of weight loss medications. This approach recognizes that obesity is a chronic disorder that may require long-term pharmacological treatment (Bray & Ryan, 2007). Hill and colleagues (1999) found that patients who lost on average 10 kg and that receive medication plus lifestyle modification regained only 32% of their weight loss the following year, which was significantly lower than the 56% weight regain in those treated with a placebo and lifestyle intervention (Hill et al., 1999). However, one obstacle with using pharmacotherapy to improve weight loss maintenance is that only one medication, orlistat, is approved by the U.S. Food and Drug Administration for long-term administration and this medication has only been shown to have modest effects (Bray & Ryan, 2007). Thus, further advances in science are required to create medications that can be used for a long period of time to help sustain weight loss.

Summary

Behavioral therapy (BT) is a popular technique that is implemented to manage obesity by targeting behaviors that restrict calorie intake and increasing physical activity (Jacob & Isaac, 2012; Stuart, 1967).  BT assumes that obesity is the result of maladaptive eating and exercise habits, where these maladaptive behaviors can be modified with specific interventions that result in weight loss. The major components of BT are that clear behavioral goals are established, it is process oriented, and it focuses on small changes (Jacob & Isaac, 2012). There are many techniques that are employed during BT: self-monitoring, stimulus control, slower eating, goal setting, and more (Jacob & Isaac, 2012). The combination of these interventions leads to approximately 8-10 kg of weight loss for participants undergoing BT. However, once treatment is terminated, patients will typically regain approximately one-third of their weight loss within a year and return to their original weight after five years (Wadden et al., 2007; Wing, 2002). Individuals can participate in long term patient-provider contact (in person, internet, or telephone), physical activity, or pharmacotherapy to sustain their weight loss (Jacob & Isaac, 2012). In summary, BT is effective in helping individuals lose their initial weight, but vigilance is required to sustain weight loss.

References

Avenell, A., Broom, J., Brown, T. J., Poobalan, A., Aucott, L., Stearns, S. C., … Grant, A. M. (2004). Systematic review of the long-term effects and economic consequences of treatments for obesity and implications for health improvement. Health Technology Assessment (Winchester, England), 8(21), iii–iv, 1–182.

Beck, A. T. (1976). Cognitive therapy and the emotional disorders. New York.

Befort, C. A., Nollen, N., Ellerbeck, E. F., Sullivan, D. K., Thomas, J. L., & Ahluwalia, J. S. (2008). Motivational interviewing fails to improve outcomes of a behavioral weight loss program for obese African American women: a pilot randomized trial. Journal of Behavioral Medicine, 31(5), 367–377. https://doi.org/10.1007/s10865-008-9161-8

Bertz, F., Brekke, H. K., Ellegård, L., Rasmussen, K. M., Wennergren, M., & Winkvist, A. (2012). Diet and exercise weight-loss trial in lactating overweight and obese women. The American Journal of Clinical Nutrition, 96(4), 698–705. https://doi.org/10.3945/ajcn.112.040196

Bray, G. A., & Ryan, D. H. (2007). Drug treatment of the overweight patient. Gastroenterology, 132(6), 2239–2252. https://doi.org/10.1053/j.gastro.2007.03.053

Butryn, M. L., Phelan, S., Hill, J. O., & Wing, R. R. (2007). Consistent self-monitoring of weight: a key component of successful weight loss maintenance. Obesity (Silver Spring, Md.), 15(12), 3091–3096. https://doi.org/10.1038/oby.2007.368

Butryn, M. L., Webb, V., & Wadden, T. A. (2011). Behavioral Treatment of Obesity. The Psychiatric Clinics of North America, 34(4), 841–859. https://doi.org/10.1016/j.psc.2011.08.006

Carels, R. A., Darby, L., Cacciapaglia, H. M., Konrad, K., Coit, C., Harper, J., … Versland, A. (2007). Using motivational interviewing as a supplement to obesity treatment: a stepped-care approach. Health Psychology: Official Journal of the Division of Health Psychology, American Psychological Association, 26(3), 369–374. https://doi.org/10.1037/0278-6133.26.3.369

Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults: executive summary. Expert Panel on the Identification, Evaluation, and Treatment of Overweight in Adults. (1998). The American Journal of Clinical Nutrition, 68(4), 899–917.

Comuzzie, A. G. (2001). The genetic contribution to human obesity: the dissection of a complex phenotype. Obesity, growth and development. London: Smith-Gordon, 21-36.

Drewnowski, A., & Rolls, B. J. (2005). How to Modify the Food Environment. The Journal of Nutrition, 135(4), 898–899.

Finucane, M. M., Stevens, G. A., Cowan, M. J., Danaei, G., Lin, J. K., Paciorek, C. J., … Ezzati, M. (2011). National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9·1 million participants. The Lancet, 377(9765), 557–567. https://doi.org/10.1016/S0140-6736(10)62037-5

Fogelholm, M., & Kukkonen-Harjula, K. (2000). Does physical activity prevent weight gain–a systematic review. Obesity Reviews: An Official Journal of the International Association for the Study of Obesity, 1(2), 95–111.

Foster, G. D. (2002). Goals and strategies to improve behavior-change effectiveness. Evaluation and management of obesity. Philadelphia: Hanley & Belfus, 29-32.

Foster, G. D. (2006). Clinical implications for the treatment of obesity. Obesity (Silver Spring, Md.), 14 Suppl 4, 182S–185S. https://doi.org/10.1038/oby.2006.303

Foster, G. D., Makris, A. P., & Bailer, B. A. (2005). Behavioral treatment of obesity. The American Journal of Clinical Nutrition, 82(1), 230S–235S.

Jacob, J. J., & Isaac, R. (2012). Behavioral therapy for management of obesity. Indian Journal of Endocrinology and Metabolism, 16(1), 28–32. https://doi.org/10.4103/2230-8210.91180

Jeffery, R. W., Wing, R. R., Sherwood, N. E., & Tate, D. F. (2003). Physical activity and weight loss: does prescribing higher physical activity goals improve outcome? The American Journal of Clinical Nutrition, 78(4), 684–689.

Jeffery, R. W., Wing, R. R., Thorson, C., Burton, L. R., Raether, C., Harvey, J., & Mullen, M. (1993). Strengthening behavioral interventions for weight loss: a randomized trial of food provision and monetary incentives. Journal of Consulting and Clinical Psychology, 61(6), 1038–1045.

Johns, D. J., Hartmann-Boyce, J., Jebb, S. A., Aveyard, P., & Behavioural Weight Management Review Group. (2014). Diet or exercise interventions vs combined behavioral weight management programs: a systematic review and meta-analysis of direct comparisons. Journal of the Academy of Nutrition and Dietetics, 114(10), 1557–1568. https://doi.org/10.1016/j.jand.2014.07.005

Harvey-Berino, J., Pintauro, S., Buzzell, P., DiGiulio, M., Casey Gold, B., Moldovan, C., & Ramirez, E. (2002). Does using the Internet facilitate the maintenance of weight loss? International Journal of Obesity and Related Metabolic Disorders: Journal of the International Association for the Study of Obesity, 26(9), 1254–1260. https://doi.org/10.1038/sj.ijo.0802051

Harvey-Berino, J., Pintauro, S., Buzzell, P., & Gold, E. C. (2004). Effect of internet support on the long-term maintenance of weight loss. Obesity Research, 12(2), 320–329. https://doi.org/10.1038/oby.2004.40

Heymsfield, S. B., van Mierlo, C. a. J., van der Knaap, H. C. M., Heo, M., & Frier, H. I. (2003). Weight management using a meal replacement strategy: meta and pooling analysis from six studies. International Journal of Obesity and Related Metabolic Disorders: Journal of the International Association for the Study of Obesity, 27(5), 537–549. https://doi.org/10.1038/sj.ijo.0802258

Hill, J. O., Hauptman, J., Anderson, J. W., Fujioka, K., O’Neil, P. M., Smith, D. K., … Aronne, L. J. (1999). Orlistat, a lipase inhibitor, for weight maintenance after conventional dieting: a 1-y study. The American Journal of Clinical Nutrition, 69(6), 1108–1116.

Klein, S., Burke, L. E., Bray, G. A., Blair, S., Allison, D. B., Pi-Sunyer, X., … Eckel, R. H. (2004). Clinical Implications of Obesity With Specific Focus on Cardiovascular Disease. Circulation, 110(18), 2952–2967. https://doi.org/10.1161/01.CIR.0000145546.97738.1E

Perri, M. G., & Corsica, J. A. (2002). Improving the maintenance of weight lost in behavioral treatment of obesity. In T. A. Wadden & A. J. Stunkard (Eds.), Handbook of obesity treatment (pp. 357–379). New York, NY, US: Guilford Press.

Perri, M. G., Limacher, M. C., Durning, P. E., Janicke, D. M., Lutes, L. D., Bobroff, L. B., … Martin, A. D. (2008). Extended-care programs for weight management in rural communities: the treatment of obesity in underserved rural settings (TOURS) randomized trial. Archives of Internal Medicine, 168(21), 2347–2354. https://doi.org/10.1001/archinte.168.21.2347

Perri, M. G., McAllister, D. A., Gange, J. J., Jordan, R. C., McAdoo, G., & Nezu, A. M. (1988). Effects of four maintenance programs on the long-term management of obesity. Journal of Consulting and Clinical Psychology, 56(4), 529–534.

Rejeski, W. J., Brubaker, P. H., Goff, D. C., Bearon, L. B., McClelland, J. W., Perri, M. G., & Ambrosius, W. T. (2011). Translating weight loss and physical activity programs into the community to preserve mobility in older, obese adults in poor cardiovascular health. Archives of Internal Medicine, 171(10), 880–886. https://doi.org/10.1001/archinternmed.2010.522

Renjilian, D. A., Perri, M. G., Nezu, A. M., McKelvey, W. F., Shermer, R. L., & Anton, S. D. (2001). Individual versus group therapy for obesity: effects of matching participants to their treatment preferences. Journal of Consulting and Clinical Psychology, 69(4), 717–721.

Rosenbaum, M., Hirsch, J., Gallagher, D. A., & Leibel, R. L. (2008). Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight. The American Journal of Clinical Nutrition, 88(4), 906–912.

Skender, M. L., Goodrick, G. K., Del Junco, D. J., Reeves, R. S., Darnell, L., Gotto, A. M., & Foreyt, J. P. (1996). Comparison of 2-year weight loss trends in behavioral treatments of obesity: diet, exercise, and combination interventions. Journal of the American Dietetic Association, 96(4), 342–346. https://doi.org/10.1016/S0002-8223(96)00096-X

Snyder, E. E., Walts, B., Pérusse, L., Chagnon, Y. C., Weisnagel, S. J., Rankinen, T., & Bouchard, C. (2004). The human obesity gene map: the 2003 update. Obesity Research, 12(3), 369–439. https://doi.org/10.1038/oby.2004.47

Stuart, R. B. (1967). Behavioral control of overeating. Behaviour Research and Therapy, 5(4), 357–365. https://doi.org/10.1016/0005-7967(67)90027-7

Svetkey, L. P., Stevens, V. J., Brantley, P. J., Appel, L. J., Hollis, J. F., Loria, C. M., … Weight Loss Maintenance Collaborative Research Group. (2008). Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial. JAMA, 299(10), 1139–1148. https://doi.org/10.1001/jama.299.10.1139

Tate, D. F., Jeffery, R. W., Sherwood, N. E., & Wing, R. R. (2007). Long-term weight losses associated with prescription of higher physical activity goals. Are higher levels of physical activity protective against weight regain? The American Journal of Clinical Nutrition, 85(4), 954–959.

Vissers, D., Verrijken, A., Mertens, I., Van Gils, C., Van de Sompel, A., Truijen, S., & Van Gaal, L. (2010). Effect of long-term whole body vibration training on visceral adipose tissue: a preliminary report. Obesity Facts, 3(2), 93–100. https://doi.org/10.1159/000301785

Volpp, K. G., John, L. K., Troxel, A. B., Norton, L., Fassbender, J., & Loewenstein, G. (2008). Financial incentive-based approaches for weight loss: a randomized trial. JAMA, 300(22), 2631–2637. https://doi.org/10.1001/jama.2008.804

Wadden, T. A., Berkowitz, R. I., Sarwer, D. B., Prus-Wisniewski, R., & Steinberg, C. (2001). Benefits of lifestyle modification in the pharmacologic treatment of obesity: a randomized trial. Archives of Internal Medicine, 161(2), 218–227.

Wadden, T. A., Berkowitz, R. I., Womble, L. G., Sarwer, D. B., Phelan, S., Cato, R. K., … Stunkard, A. J. (2005). Randomized trial of lifestyle modification and pharmacotherapy for obesity. The New England Journal of Medicine, 353(20), 2111–2120. https://doi.org/10.1056/NEJMoa050156

Wadden, T. A., Butryn, M. L., & Wilson, C. (2007). Lifestyle modification for the management of obesity. Gastroenterology, 132(6), 2226–2238. https://doi.org/10.1053/j.gastro.2007.03.051

Wadden, T. A., & Foster, G. D. (2000). Behavioral treatment of obesity. Medical Clinics of North America, 84(2), 441-461.

Wadden, T. A., Vogt, R. A., Foster, G. D., & Anderson, D. A. (1998). Exercise and the maintenance of weight loss: 1-year follow-up of a controlled clinical trial. Journal of Consulting and Clinical Psychology, 66(2), 429–433.

Webber, K. H., Gabriele, J. M., Tate, D. F., & Dignan, M. B. (2010). The effect of a motivational intervention on weight loss is moderated by level of baseline controlled motivation. International Journal of Behavioral Nutrition and Physical Activity, 7, 4. https://doi.org/10.1186/1479-5868-7-4

Wing, R. R. (2002). Behavioral weight control. Handbook of obesity treatment, 2, 301-317.

Wing, R. R., Jeffery, R. W., Burton, L. R., Thorson, C., Nissinoff, K. S., & Baxter, J. E. (1996). Food provision vs structured meal plans in the behavioral treatment of obesity. International Journal of Obesity and Related Metabolic Disorders: Journal of the International Association for the Study of Obesity, 20(1), 56–62.

Wing, R. R., & Phelan, S. (2005). Long-term weight loss maintenance. The American Journal of Clinical Nutrition, 82(1 Suppl), 222S–225S.

Wing, R. R., Tate, D. F., Gorin, A. A., Raynor, H. A., & Fava, J. L. (2006). A self-regulation program for maintenance of weight loss. The New England Journal of Medicine, 355(15), 1563–1571. https://doi.org/10.1056/NEJMoa061883

World Health Organization. (2009). Global health risks: mortality and burden of disease attributable to selected major risks. World Health Organization.