Do we know how common eating disorders are in people with diabetes? Someone with type 1 diabetes and anorexia or bulimia nervosa is very visible because they require an enormous amount of support, and may frequently present with episodes of severe hypoglycaemia or diabetic ketoacidosis. Binge eating may be common in overweight people with type 2 diabetes (Mannucci et al, 2002) but may be easily missed.
The steady rise in the prevalence of type 2 diabetes is related to increasing obesity levels, with the latest figures from Diabetes UK (2010) showing that there are 2.8 million people with diabetes in the UK, most of whom have type 2. The strong association of most cases of type 2 diabetes with obesity has led to the term “diabesity” by some authors (Astrup and Finer, 2000). Obesity and type 2 diabetes are therefore often seen as the “norm”, and rather than exploring underlying mental health issues contributing to the obesity, the focus is on encouraging the person to reduce calorie intake and lose weight to ameliorate the effects excess weight have on metabolic control through insulin resistance.
Is binge eating a cause or effect of type 2 diabetes? As the onset of type 2 diabetes is usually much later than that of eating disorders, it is unlikely to be the effect of diabetes. Binge eating may increase the risk of developing the components of metabolic syndrome over and above the risk attributable to obesity alone (Hudson et al, 2010), and so increase the risk of developing type 2 diabetes. Abnormalities of eating behaviour are also associated with poorer metabolic control in people with established diabetes (Mannucci et al, 2002).
However, it may be difficult to identify if someone has an eating disorder if they have diabetes, for a number of reasons. These include the effect of insulin therapy, loss of satiety mechanisms via hormonal dysregulation seen in diabetes, the emphasis on food and diets in diabetes self-care programmes, and psychological issues such as loss of control (Young-Hyman and Davis, 2010). Some antidiabetes agents, especially insulin, may increase hunger and promote weight gain, or at least make it difficult to lose weight. Newer agents based on the incretin system that aid weight loss, or at least improve glycaemic control without weight gain, are a welcome addition to the choice of therapeutic agents for this reason.
Screening people for eating disorders may be difficult. NICE advises that “Young people with type 1 diabetes and poor treatment adherence should be screened and assessed for the presence of an eating disorder” (National Collaborating Centre for Mental Health [NCCMH], 2004). Readers of this editorial who work in a diabetes adolescent clinic may think that is the majority of their patients! There are a confusing number of questionnaires available, including the Binge Eating Scale, Eating Attitudes Test, Eating Disorders Inventory, and the Diagnostic Survey for Eating Disorders. However, these have been developed for people without diabetes and some questions may be answered positively by anyone with diabetes, for example I feel that food controls my life (Young-Hyman and Davis, 2010).
Once identified, the management of someone with type 2 diabetes and binge eating disorder will differ from the usual strategies. Treating obesity in diabetes is focused on reducing calories, increasing activity, structured patient education, dietetic support, weight management groups, prescribing of obesity agents (now reduced to a single choice) and, for people with significant obesity, bariatric surgery (NICE, 2006). Although these familiar interventions will still be required, the language in the management of binge eating is very different: cognitive behaviour therapy, interpersonal psychotherapy, and modified dialectical behaviour therapy (NCCMH, 2004). Supporting overweight people to lose weight has never been easy and identifying and addressing eating disorders adds to the complexity, but hopefully will make what we’re doing more effective.