IB Docs (2) Team
Strategies for reducing obesity
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Since prevention strategies are not 100% successful in reducing obesity, psychologists have to study ways in which they can help those who are already obese and need to lose weight. As there are different approaches to explaining the origin of the problem, there are different treatments that are used with the hope of helping the patient.
In this section was are going to look at three examples of treatments for obesity. The first example is a drug-based treatment. The second treatment is mindfulness. The third strategy is Cognitive Behavioural Therapy.
Please note that this is not a required part of the IB curriculum. However, when discussing problems, it is not a bad idea to think about potential solutions...
Drug treatments
Doctors do not recommend drug treatments as the sole remedy for obesity but recommend a comprehensive program. They encourage drug treatments as an addition to change in eating habits - particularly calorie intake - and an increase in activity.
Two different drugs
There are two types of drugs that are prescribed: appetite suppressants and lipase inhibitors.
Appetite-suppressant drugs (such as Belviq) promote weight loss by decreasing appetite or increasing the feeling of being full because they increase the level of neurotransmitters that affect mood and appetite. There is some evidence for the effectiveness of these drugs, although they have some side effects, such as nausea, constipation, and dry mouth.
Lipase inhibitors (such as Orlistat or Xenical) act on the gastrointestinal system and reduce fat absorption. There may be a range of unpleasant side effects, especially after eating a meal with high-fat content. This could probably have a preventive effect, since eating fat becomes associated with unpleasant consequences. The following video demonstrates how this works. Please note carefully when watching the video the side-effects of the drug.
Berkowitz et al. (2006) carried out a longitudinal study with a sample of 498 obese adolescents (age range 12–16 years). The aim of the study was to investigate if an appetite-suppressant drug (sibutramine) reduced weight more than a placebo. The participants were randomly allocated to either receive the drug or to receive the placebo. In order to represent current practice in medicine, the participants also received counseling about how to eat less food, increase physical activity, reduce stress, and keep track of how much they ate.
Adolescents who took the appetite suppressant usually lost weight (6.4kg) during the first months of the trial. Those who took the placebo usually gained weight (1.8kg). The weight loss tended to be faster at the beginning of the study and then eventually their weight was maintained.
There are a few limitations of the study. First, there were side-effects of taking the drug. This included increased heart-rate. In addition, even though this was a longitudinal study, there was no follow-up study to determine if the participants were able to maintain their weight loss.
Jain et al (2011) carried out a study on the effectiveness of Orlistat in treating obesity. Their sample included 80 obese patients who were randomly allocated to one of two conditions. The first group received 120 mg of Orlistat three times a day; the second group received a placebo three times a day. The groups were matched for BMI and cholesterol levels. In addition to the drug treatment, participants were counseled in exercise, diet and stress management.
Compared to the placebo, Orlistat caused a significant reduction in weight, BMI and cholesterol levels. The average weight loss was 4.65 kg vs. 2.5 kg in the placebo group. Notice that the change in behaviour alone resulted in weight loss, but the drug treatment increased weight loss over a shorter period of time. As with the Berkowitz study, the long-term maintenance of weight loss was not studied, but it is argued that the comprehensive treatment will help to maintain the weight loss.
Finally, Yanovski & Yanovski (2014) carried out a meta-analysis of placebo-controlled trials for approved obesity medications. All studies had a sample of at least 50 participants and lasted at least one year. They found that medications approved for long-term obesity treatment when used as in addition to lifestyle intervention, lead to greater mean weight loss and an increased likelihood of achieving clinically meaningful 1-year weight loss relative to placebo.
Mindfulness-based eating awareness training
Kristeller's work on Mindfulness-based eating awareness training focuses on the assumption that if we can become more aware of our own physical state - that is, whether we are hungry, full, bored, stressed, etc. - then we will respond to food in a more productive and healthy way. Part of mindfulness is also to slow down and "live in the present." In our modern world, food is often "functional" and quickly consumed during short breaks in our busy schedules. Kristeller argues that by learning to focus on our food and enjoy it will cut down on the need to consume so many calories.
This is linked to research on stress being carried out by Elissa Epel on the relationship between stress and overeating.
Kristeller, Wolever & Sheets (2013) carried out a study to test the effectiveness of MB-EAT (Mindfulness-Based Eating Awareness Training) compared to CBT. The study randomly allocated 150 participants to one of three conditions: A 12-week MB-EAT program, a CBT intervention, or a wait-list control. A wait-list control is a group that is willing to use the MB-EAT and/or CBT treatments, but is not given treatment for the duration of the study. All of the participants were obese, with 66% of them meeting the full DSM-IVR criteria for binge eating disorder.
Compared to the wait-list condition, both MB-EAT and the CBT treatment showed improvement. At four months after the MB-EAT treatment had completed, 95% of those diagnosed with binge eating disorder no longer met the criteria for that diagnosis. This compared to 76% of those who received the CBT treatment. Their conclusion was that the amount of mindfulness practice predicted weight loss and a decrease in binge eating behaviours.
O'Reilly et al (2014) carried out a meta-analysis of research done on Mindfulness-based interventions (MBIs) on treating obesity and eating behaviours. One of the problems with the research was the lack of peer-reviewed research as this is still a very new field of study. The researchers reviewed 21 studies and found that 86% of the studies reported improvements in eating behaviours. However, as with the drug treatments discussed above, the research covered a large range of intervention variables, including mixing MBI with CBT, exercise, medication and other approaches to weight management.
Madsen et al (2009) argue that although mindfulness may have benefits, it also is competing with a food environment that is related to socioeconomic status. Children living in poverty often live in high-stress communities where affordable food is often high in fats and sugar. It is in these communities where obesity levels are highest.
Results from her study found that neither the mindfulness group nor the control group changed their metabolic profile by much, though both groups did have overall reductions in anxiety and in the kids’ body mass index scores. She argues that it is the food environment in which these children live that provides an unhealthy diet. This has to change in order for mindfulness - or any other program - to be effective.
Cognitive Behavioural Therapy
CBT aims to change how people think about eating as well as their eating behaviour. The therapy targets those thoughts and beliefs that prevent the patient from losing weight when they have decided to do so. The important thing is not why the patient is overeating, but dealing with cognitions that lead directly to eating. CBT must focus on the patient’s permission-giving beliefs that lead to overeating - for example, “It’s okay to eat now because I am upset.”
Stahre et al. (2007) conducted a randomized trial with a group of 42 obese women in Sweden. 16 of them participated in a program that included elements of CBT, and 20 participated in a control group that included moderate-intensity physical activity. The treatment lasted for 10 weeks (two hours per week). The participants’ weight was controlled periodically over an 18-month period.
In the cognitive program, the weight loss was 8.6kg at the end of the treatment and 5.9kg after the 18-month follow-up. Participants in the control group had lost an average of 0.7kg, and after the 18-month follow-up, they had gained 0.3kg on average. Although the difference between the two groups is statistically significant, it is important to note two key limitations of the study. First, it is a very limited sample size. Secondly, only women were tested. In addition, the mean weight of the women was 100.3 kgs with a standard deviation of 14.8 kgs. This raises questions as to the number of women that lost enough weight to be considered in the healthy range of BMI.
In spite of these two studies showing that CBT may have some effect on eating behaviours, the vast majority of the research shows that CBT does not have a long-term effect on weight loss. Cooper et al (2010) carried out a long-term study of 150 female participants with obesity who were randomly allocated to either CBT for a period of 44 weeks or a guided self-help program for 24 weeks. The CBT treatment resulted in an average weight loss of about ten percent of initial weight, compared to minimal weight loss in the self-help program. The participants were subsequently followed-up for three years post-treatment. The great majority regained almost all the weight that they had lost with the CBT treatment. The researchers suggest that it is ethically questionable to claim that psychological treatments for obesity “work” in the absence of data on their longer-term effects.
One of the arguments against CBT is the idea that we have a set-point for our weight. Watch this video to get a better understanding of what that might mean.
ATL: Critical thinking
After reading this chapter on strategies for reducing obesity, which of the three strategies described above would you recommend to a friend that was struggling with obesity? Rank the three strategies in order of desirability. Be able to justify your response.
Checking for understanding
1. What is a lipase inhibitor?
A lipase inhibitor is a drug that reduces fat absorption in the intestines. The idea is that by taking lipase inhibitor we do not store fat, but excrete it.
2. Why are placebos important in drug studies on reducing obesity?
Placebos are used because it could be that simply taking a drug may lead one to change behaviour - either consciously or unconsciously - that would result in the desired effect. A placebo strives to show that taking a pill alone is not what led to weight loss, but the actual drug itself.
3. Why is it not possible to argue that drug treatment is the best treatment for obesity?
The vast majority of studies done on drug treatments involve a comprehensive approach to weight loss - including dieting, exercise and stress management. Even those studies where drugs are tested without a comprehensive approach, cannot control for these other variables.
4. What does it mean when we say that groups were matched for BMI and cholesterol levels?
It means that even though the participants were randomly allocated, they were first sorted by BMI and cholesterol levels - and then randomly allocated so that both groups had a similar distribution of BMI and cholesterol levels.
5. What are two limitations of research on mindfulness-based approaches to obesity?
First, the field is relatively new. Therefore, there is not a large number of peer-reviewed studies on the topic. Secondly, just as with other treatments, it is difficult to control for environmental and biological variables that may affect the outcomes of the studies.
6. What are the basic assumptions or theories upon which CBT is based?
CBT is based on the idea that if we can restructure how we think, we can change our behaviours. It is also based on the idea that we have schemas that help us to make decisions about how we behave. For example, eating potato chips helps me to relax or Now that I have finished my work, I am going to reward myself by getting drunk or eating a high calorie dessert. The goal of CBT is change these thinking patterns so that we have more healthy eating behaviours.
7. Why might CBT not be an effective means of treating obesity?
CBT may not work because body weight is the product of genetic effects (DNA), epigenetic effects (heritable traits that do not involve changes in DNA), and the environment. Simply changing one's thinking patterns may not be enough.
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