Eating disorders and obesity: two sides of the same coin?

Abstract

The eating disorders anorexia and bulimia nervosa have traditionally been regarded as entirely separate from obesity. Eating disorders have been regarded as Western culture-bound syndromes, arising in societies with excessive emphasis on weight, shape and appearance, and best treated by psychological therapies, in particular cognitive behavioural therapy or familybased interventions. In contrast, obesity has been considered a medical illness with metabolic and genetic origins, and thought to be best treated by mainstream medicine, involving dietary, drug or surgical treatment. We believe that this polarisation is fundamentally flawed, and research and treatment of both types of disorder would be better served by greater appreciation of the psychosocial components of obesity and the biological and genetic components of eating disorders. There are similarities in phenotype (such as excessive attempts at weight control, binge eating behaviours) and in risk factors (such as low self-esteem, external locus of control, childhood abuse and neglect, dieting, media exposure, body image dissatisfaction, weight-related teasing and shared susceptibility genes). One example of shared genetic risk is the brain-derived neurotrophic factor (BNDF) gene, in which the valine allele of the Va166Met amino acid polymorphism predisposes to obesity, whereas the methionine allele predisposes to eating disorders. Thus the evidence suggests that these disorders will have both shared and distinct susceptibility factors; some will predispose to both types of disorder, some will push in opposite directions, and some will separate them.

Evidence for three genetic loci involved in both anorexia nervosa risk and variation of body mass index

“…While only one study has suggested an interaction between CTBP2 and BDNF 47 , the interaction of CARF and BDNF has been substantiated in numerous studies (see above). Thus, again as BDNF might be involved in both AN and obesity 27,101,102 this gene is biologically highly plausible.…”

Prevalence of binge and loss of control eating among children and adolescents with overweight and obesity: An exploratory meta‐analysis

“…Research in this area suggests that shared risk factors between obesity and disordered eating behaviors should be considered (Day et al, ; Haines and Neumark‐Sztainer, 2006; Haines et al, ). For instance, according to a literature review conducted by Haines and Neumark‐Sztainer, factors, such as body dissatisfaction and weight‐related teasing, were suggested to be potential shared risk factors for obesity and binge eating (Haines and Neumark‐Sztainer, 2006).…”

A school-based program implemented by community providers previously trained for the prevention of eating and weight-related problems in secondary-school adolescents: the MABIC study protocol

“…In particular, special attention is being paid to shared risk factors of eating disorders and obesity [70,72-75], and calls for the development of an integrated approach to prevention in both fields are increasing [59,70,76-78]. …”