Disordered eating is a complex problem which takes a variety of forms.
Anorexia nervosa is characterized by restrictive eating behaviours and excessive exercise which lead to medically dangerous weight loss.
Bulimia nervosa is characterized by binge-eating, and by purging (most commonly, self-induced vomiting). During binges, people often feel out of control, unable to stop.
In many cases, individuals have a mixture of anorexic and bulimic symptoms, without having a full syndrome of anorexia or bulimia.
In most cases of any eating disorder, there is a prominent disturbance of body image. Individuals may feel disgusted with their physical appearance. There may be an extremely strong preoccupation with fat. Fat (the word itself, as well as everything it represents) becomes something to be feared, avoided, and reviled. Any perception of normal subcutaneous fat is met with self-criticism or loathing. A perception of becoming thinner can be met with a feeling of satisfaction or addictive euphoria. Dietary fat, and dietary calories, often become subjects of intense preoccupation. Planning meals, or thinking about past meals, can lead to a great deal of anxiety. Eating socially with others can be extremely difficult. Situations in which people are more physically exposed (e.g. swimming pools, or the outdoors on a hot summer day) can cause increased self-consciousness and consequent self-loathing. Therefore, these situations are often avoided. Physical comparisons with other people can intensify symptoms. Many eating disorder behaviours (such as binges and purges) occur in secret.
Eating disorders can be medically dangerous: severe anorexia nervosa can be fatal. Other metabolic abnormalities from starvation or purging can cause weakness, cognitive impairments, bone demineralization, and abnormal heart rhythms. Repeated vomiting can cause damage to the esophagus. Overall poor nutrition makes it hard to treat other mental health problems, such as anxiety or depression.
In the treatment of eating disorders, sometimes a hospital stay is needed if weight is dangerously low.
Effective long-term resolution of severe symptoms can begin with an intensive multi-disciplinary day program, and may require lifelong treatment.
But here are a few basic ideas that I think can help in a less intensive outpatient setting:
1) It is important to be well-educated about basic nutrition -- to know what your body needs in a day, in terms of calories, fat, protein, vitamins, etc -- and to have a good sense of what foods might contain this balance of nutrients in a typical day. A consult with a dietician can be helpful.
2) Regular meals are important. Having regular meals can reduce the tendency to binge, since hunger will not build up as intensely. Experiencing meals is a component of behavioural therapy: planning the meal, obtaining & preparing the food, consuming the food, and then allowing the food to stay inside and be digested without purging. Each of these aspects may carry a lot of anxiety and stress. Having interpersonal support during these times can be powerfully helpful. Cognitive-behavioural techniques could also be helpful to manage the anxiety.
3)It can be important to recognize familiar patterns of thinking (e.g. having to do with fat or caloric calculations, dieting, weight loss plans, etc.) and practicing ways of directing attention away from these themes. It is also unhelpful to be bombarded with these themes in your social or cultural life, so I encourage a practice of redirecting social, cultural, or conversational energy away from subjects such as dieting, weight loss, etc.
4) Antidepressants such as SSRIs can help with bulimia (reference: http://www.ncbi.nlm.nih.gov/pubmed/14583971). The anticonvulsant topiramate can help reduce binge eating (references: http://www.ncbi.nlm.nih.gov/pubmed/18774432; http://www.ncbi.nlm.nih.gov/pubmed/14728106). Pharmacologic treatments for anorexia have not yet been very successful.
5) I think a very important element to work on is the confrontation and challenge of negative body image, its associated language, and its associated impairment in sensuality. Steps may need to be taken to stop or challenge "negative self-talk" and criticism about your body--about the way your body looks in a mirror, or the way your body feels to touch. This negative self-talk, and the ensuing negative emotions, need to be replaced by affirmations and by enjoyment. I think this type of work needs to be done every day. It can sometimes require work to gain pleasure from something, or to learn how to experience pleasure: this is a theme strongly present in the treatment of depression as well. Actually, I think it is a theme present in life generally -- we need to learn and practice something, to be with it consistently, in order for love or enjoyment to grow.
6) Similarly, I think it is important to reclaim the sensuality of food: the process of planning, preparing, consuming, and digesting food needs to be transformed from a source of dread or anxiety to a set of simple life pleasures. I think this type of sensuality should be emphasized in behavioural therapeutic techniques. Mindfulness meditation techniques can be helpful along these lines.