The DSM-5 proposes the following as weight disorders: anorexia nervosa, bulimia nervosa, binge eating disorder, pica, rumination disorder, evident/restrictive intake disorder, other specified feeding or eating disorder and unspecified feeding or eating disorder. The three most common eating disorder are anorexia nervosa, bulimia nervosa and binge eating disorder. anorexia nervosa is characterised by low weight, fear of gaining weight and an intense desire to be skinny and heavy food restrictions and limitations. Bulimia nervosa is characterised as an eating disorder with two parts; eating excessively large quantities and then purging (vomitting or taking laxatives). Binge eating disorder is characterised as eating excessively large quantities without purging afterwards.
The references below you may find useful with further research!
ref: Grilo, C. M. (2014). Eating and weight disorders. Psychology Press.
Thompson, J. K., & Smolak, L. (Eds.). (2001). Body image, eating disorders, and obesity in youth: Assessment, prevention, and treatment. Taylor & Francis.
Brownell, K. D., & Fairburn, C. G. (1995). Eating disorders and obesity: A comprehensive handbook. Guilford Press.
Overall, this is a basic, but sufficient chapter which could be improved by citing more original and recent sources (rather than old references that I doubt were consulted and websites). Also, add a Conclusion, and provide separate conclusions and clearer explanations for how anxiety may lead to weight loss or weight gain. Also make more clear how weight loss or gain may influence anxiety compaed to anxiety influencing weight gain or loss.