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Psychological factors contributing to binge eating and obesity

Emma Morrow
MA(Hons) DClinPsy
Clinical Psychologist
Eating Disorder Service
Royal Cornhill Hospital
Aberdeen

Binge eating disorder (BED) is one of the lesser-known and less researched eating disorders in comparison with anorexia nervosa and bulimia nervosa. The inclusion of BED as a subcategory of "Eating Disorders Not Otherwise Specified" (EDNOS) in the Diagnostic and Statistical Manual of Mental Disorders resulted in a surge of research activity around the condition.(1)
BED is characterised by episodes of binge eating that feel uncontrollable. Unlike in bulimia nervosa, there are no compensatory purging behaviours such as self-induced vomiting or laxative abuse. Many individuals with BED are overweight or obese, thus increasing their risk of medical complications and mortality.
Binge eating can be particularly difficult to define. This may be because most people engage in some form of overeating from time to time and many people perceive their regular food intake to be excessive. From a diagnostic perspective, binge eating involves consuming an unusually large amount of food within a short time period (less than two hours), accompanied by a sense of loss of control. "Subjective" binges may occur when a loss of control is experienced, even if the amount of food is within "normal" limits. It is therefore important to clarify the actual amount of food consumed as well as the patient's perception of the amount they have eaten.
The signs and symptoms of BED include:

  • Rapid eating.
  • Sensation of uncomfortable fullness.
  • Large quantities of food consumed, despite not feeling hungry.
  • Eating while alone.
  • Experience of shame and embarrassment due to the quantities of food being consumed.
  • Feelings of disgust and guilt following binge eating episodes.
  • Distress and social avoidance.
  • Symptoms of depression.
  • Dissatisfaction with shape.
  • Weight gain.

The physical complications that accompany BED tend to be diseases that are caused by obesity, such as diabetes, heart disease, elevated cholesterol and blood pressure.
BED may cause extreme distress for sufferers, particularly if it has a long-standing history. It may affect their ability to lead the life they want, placing limitations on their occupational functioning, their family life and their social functioning. Low self-esteem commonly accompanies BED, and this may be exacerbated by the disgust and shame experienced in response to frequent binge eating. The secrecy that typically occurs in this disorder may result in limits on social support from friends and family due to their lack of awareness of the problem. Feelings of shame may also prevent sufferers from seeking professional help.
It is important to gain as much historical information relating to the individual's eating as possible. It is most likely that people with BED will present with a history of overeating, rather than restrained intake of food.

Epidemiology
BED tends to initially develop in the teens or early twenties, although sufferers are most likely to seek help in their thirties or forties, possibly due to difficulties with overweight or obesity. Some studies have shown that more women than men suffer from BED, although the gender difference is less marked than in other eating disorders. Men have been shown to report less distress associated with BED.(2) The prevalence of BED varies from 2% within community samples to over 25% in treatment-seeking obese populations.(3,4)

Aetiology
There are a number of potential causes of BED, although the exact aetiology is not clear. It has been proposed that, as in other eating disorders, the desire of many to be thin, and the association between thinness and attractiveness, may result in disordered eating. Furthermore, it has been suggested that chronic dieting contributes to binge eating behaviour, potentially due to depriving oneself of desired foods. The fact that many deem overweight or obesity unattractive may result in dissatisfaction with one's body, further encouraging dieting behaviour, and consequently increasing the likelihood of binge episodes.
Many people who suffer from BED have a history of depression. However, this may be also linked to the relationship between obesity and BED. It is difficult to establish whether obesity may have influenced the depression, or vice versa. Similarly, low self-esteem appears to be a contributing factor to BED. A recent study demonstrated that women with BED report exposure to a higher number of distressing life events in the 12 months before the onset of their eating disorder, including work stress, major life changes, physical abuse and critical comments about appearance.(5)
A range of internal and external events, including anger, sadness, boredom, anxiety and stressful life events, may trigger binges. Patients may feel that bingeing provides a means of coping with distress, possibly through the mechanism of distraction. The occurrence of binges may be linked to the presence of cognitive distortions, such as all-or-nothing thinking, whereby the patient may believe that eating a small amount of food they regard as forbidden is a failure on their part, subsequently leading to consuming a large amount of such food.
Binge eating is a mental disorder but may also be influenced by the physiological effects of overeating. Bingeing results in a surge of blood glucose, stimulating insulin production by the pancreas. Following the initial "rush", blood sugar levels rapidly decline, indicating to the brain that more food is required to "top up" levels of glucose. This process makes it more likely that
cravings for high-sugar foods will occur.

What are the links between BED and weight gain?
BED may be a significant risk factor for weight gain in the future, even among those who are not obese. Research indicates that most patients with BED are not in fact obese, and almost half are not even classed as overweight.(6) However, binge eating has been shown to precede dieting in half of BED patients and may also precede the development of obesity.(7) Community studies have shown that those with BED gained an average of 9.8kg throughout a five-year period.(6)

Psychological treatment
Psychological treatment approaches for BED have largely been developed from those treatments found to be successful in alleviating bulimia nervosa. The current best-evidence treatment approach is cognitive behavioural therapy for BED (CBT-BED), a modified version of CBT for bulimia nervosa. This approach involves assisting patients in establishing healthy eating routines, self-monitoring of dietary intake, development of problem solving skills, cognitive restructuring and relapse prevention. CBT-BED demonstrates a significant reduction in the frequency of binge eating compared with waiting list controls.8
Some cognitive behavioural techniques can be implemented via self-help formats. Both guided self-help (with support provided by a health professional) and independent self-help approaches have been shown to be helpful in reducing binge eating pathology.(6) Self-help approaches have also been successful within a group format. Such formats are advantageous in terms of cost and ease of dissemination to patients.
There has also been recent growth in the use and evaluation of other therapeutic approaches, such as interpersonal therapy and simplified dialectical behaviour therapy. Both therapies have been shown to be of comparable efficacy in reducing binge eating in a group setting.(9) CBT aims to target underlying negative emotional states that may influence binge eating behaviours. Early evidence suggests a reduction in binge eating pathology, although long-term effects have not been verified.(10)
All current treatment approaches appear to be limited in their effectiveness in reducing weight for those patients who are overweight or obese. This remains an area worthy of further research.

The role of primary care clinicians
Patients with BED and other eating disorders may initially present to services within a primary care setting. In order to help identify patients who may require specialist help, patients who are at a high risk of developing such problems could be targeted. These include adolescents (particularly young women), patients with diabetes mellitus, and overweight and obese patients. It may be helpful to devise a number of screening questions to assist in the identification of such disorders. Some suggestions are provided in Table 1. Evidence suggests that the earlier eating disorders are detected, the more favourable the prognosis, so identification within primary care is important in terms of treatment outcome. For BED in particular, self-help approaches are deliverable within the primary care setting (see Resources). However, a continuing challenge for both primary care and specialist services are those patients who suffer comorbid eating disorders and obesity.

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References

  1. American Psychiatric Association. DSM-IV: Diagnostic and statistical manual of mental disorders, 4th ed. Washington, DC: APA; 1994.
  2. Lewinsohn PM, Seeley JR, Moerk KC, Striegel-Moore RH. Gender differences in eating disorder symptoms in young adults. Int J Eat Disord 2002;32:426-40.
  3. Bruce B, Agras WS. Binge eating in females: a population-based investigation. Int J Eat Disord 1992;12:365-73.
  4. Yanovski, SZ. Binge eating disorder: current knowledge and future directions. Obesity Res 1993;1:306-18.
  5. Pike KM, Wilfley D, Hilbert A, Fairburn CG, Dohm FA, Striegel-Moore RH. Antecedent life events of binge eating disorder. Psychiatry Res 2006;142:19-29
  6. Fairburn CG, Cooper Z, Doll HA, Norman, P, O'Connor, M. The natural course of bulimia nervosa and binge eating disorder in young women. Arch Gen Psychiatry 2000;5:659-65.
  7. Dingemans AE, Bruna MJ, van Furth EF. Binge eating disorder: a review. Int J Obes Relat Metab Disord 2002;26:299-307.
  8. National Institute for Clinical Excellence. NICE: Eating disorders: core interventions in the treatment and management of anorexia nervosa, bulimia nervosa and related eating disorders. London: British Psychological Society/Gaskell; 2004.
  9. Wilfley DE, Welch RR, Stein RI, Spurrell EB, et al.
    A randomized comparison of group cognitive
    behavioural therapy and group interpersonal
    psychotherapy for the
    treatment of overweight individuals with binge eating disorder. Arch Gen Psychiatry 2002;59:713-21.
  10. 10. Telch CF, Agras WS, Linehan MM. Dialectical behaviour therapy for binge eating disorder. J Consult Clin Psychol 2001;69:1061-5.
  11. Anstine D, Grinenko D. Rapid screening for disordered eating in college-aged females in the primary care setting. J Adolesc Health 2000;26:338-42
  12. Morgan JF, Reid F, Lacey JH. The SCOFF questionnaire: assessment of a new screening tool for eating disorders. BMJ 1999;319:1467.

Resources:

Self-help texts for BED
Cooper PJ.  Bulimia nervosa and binge eating. A guide to recovery. London: Robinson; 1995.

Fairburn CG. Overcoming binge eating. New York & London: Guilford Press; 1995.

Schmidt U, Treasure J. Getting better bit(e) by bit(e). Survival kit for sufferers of bulimia nervosa and binge eating disorders. Hove: Psychology Press; 1993.