Clinicians will often follow a diagnostic checklist to test whether or not an individual is exhibiting behaviors and characteristics that may lead to a diagnosis of ARFID. Clinicians will look at the variety of foods an individual consumes, as well as the portion size of accepted foods. They will also question how long the avoidance or refusal of particular foods has lasted, and if there are any associated medical concerns, such as malnutrition. Unlike most eating disorders, there may be a higher rate of ARFID in young boys, than there is in young girls.

With time the symptoms of ARFID can lessen and can eventually disappear without treatment. However, in some cases treatment will be needed as the symptoms persist into adulthood. The most common type of treatment for ARFID is some form of cognitive-behavioral therapy. Working with a clinician can help to change behaviors more quickly than symptoms may typically disappear without treatment. Also hypnotherapy may be used. In that it lessens the anxiety associated with food.

There are support groups for adults with ARFID.

Few studies to date have examined OSFED prevalence. The largest community study is by Stice (2013), who examined 496 adolescent females who completed annual diagnostic interviews over 8 years. Lifetime prevalence by age 20 for OSFED overall was 11.5%. 2.8% had atypical AN, 4.4% had subthreshold BN, 3.6% had subthreshold BED, and 3.4% had purging disorder. Peak age of onset for OSFED was 18–20 years. NES was not assessed in this study, but estimates from other studies suggest that it presents in 1% of the general population.

A few studies have compared the prevalence of EDNOS and OSFED and found that though the prevalence of atypical eating disorders decreased with the new classification system, the prevalence still remains high. For example, in a population of 215 young patients presenting for ED treatment, the diagnosis of EDNOS to OSFED decreased from 62.3% to 32.6%. In another study of 240 females in the U.S. with a lifetime history of an eating disorder, the prevalence changed from 67.9% EDNOS to 53.3% OSFED. Although the prevalence appears to reduce when using the categorizations of EDNOS vs. OSFED, a high proportion of cases still receive diagnoses of atypical eating disorders, which creates difficulties in communication, treatment planning, and basic research.

Few studies guide the treatment of individuals with OSFED. However, cognitive behavioral therapy (CBT), which focuses on the interplay between thoughts, feelings, and behaviors, has been shown to be the leading evidence-based treatment for the eating disorders of BN and BED. For OSFED, a particular cognitive behavioral treatment can be used called CBT-Enhanced (CBT-E), which was designed to treat all forms of eating disorders. This method focuses not only what is thought to be the central cognitive disturbance in eating disorders (i.e., over-evaluation of eating, shape, and weight), but also on modifying the mechanisms that sustain eating disorder psychopathology, such as perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties. CBT-E showed effectiveness in two studies (total N = 219) and well maintained over 60-week follow-up periods. CBT-E is not specific to individual types of eating disorders but is based on the concept that common mechanisms are involved in the persistence of atypical eating disorders, AN, and BN.

There are two assessment tools used to diagnose emetophobia; the Specific Phobia of Vomiting inventory and the Emetophobia Questionnaire. The Specific Phobia of Vomiting Inventory and the Emetophobia Questionnaire are both self-report questionnaires that focus on a different range of symptoms.

There have been a limited number of studies in regard to emetophobia. Victims of the phobia usually experience fear before vomiting, but feel less afterwards. The fear comes again however, if the victim fears they will throw up again.

Also noted in the emetophobia internet survey was information about medications. People were asked whether they would consider taking anxiety medication to potentially help their fear, and many in the study answered they wouldn't for fear that the drugs would make them nauseated. Others, however, stated that some psychotropic medications (such as benzodiazepines and antidepressants) did help with their phobia, and some said gastrointestinal medications were also beneficial.