Views of patients, their families, health professionals and researchers have been published on the issue.
It has suggested a series of recommendations, including improving early diagnosis, health workers' knowledge and training.
The Welsh government said it had invested in improving eating disorder services.
Campaigner Manon Lewis, who has suffered with an eating disorder, said: "We need to improve knowledge and understanding throughout all parts of the health service so that people can get the appropriate support as soon as possible."
The Cross Party Group on Eating Disorders wants to see changes across the board.
Its report said: "It is clear that there needs to be improvements in how primary care responds to and supports people with eating disorders and their families/carers."
A Welsh government spokesman added: "Community treatment for adults, which includes 18 and 19-year-olds, receives Â£1m annual funding and, since 2013, an extra Â£250,000 annual funding to improve treatment for children and young people.
"The extra funding has enabled the recruitment of specialist staff, improved training for existing staff, created extra outpatient clinics and the increased the availability of high care beds in children and adolescent mental health services."
Improvements need to be made in diagnosing and treating people with eating disorders, a report has said.