The investigators have developed a new integrated therapy, namely a Healthy Approach to weIght management and Food in Eating Disorders (HAPIFED). HAPIFED is an enhanced behavioral weight loss therapy integrated with CBT for the management of EDs. HAPIFED uses CBT to treat ED behaviors and body image distress, whilst simultaneously emphasize a healthy lifestyle, the role of food and physical activity in mood regulation, and revised but clinically meaningful goals for weight loss. The investigators propose a randomized controlled trial (RCT) that will compare HAPIFED to CBT-E in people with obesity and either BN or BED. The two main aims will be to reduce symptoms of ED and to improve weight management. The RCT will be conducted in Sydney and in São Paulo with a one year follow-up.

In sum, a new approach in management of the increasing numbers of obese people with BN and BED is needed. The investigators propose a RCT that will compare a novel therapy HAPIFED with the current 'gold-standard' trans diagnostic treatment, CBT-E. HAPIFED has been developed by the CIs and is based on recent developments in psychological approaches to obesity in general (as highlighted in Casazza et al.'s (2013) paper on "Myths, presumptions and facts about obesity") and in people with co-morbid obesity and BN or BED. Unlike CBT-E, it allows reduced energy intake and education around specific food choices - a necessary element in weight loss.

Inclusion Criteria:

• Diagnosis of threshold or subthreshold for Bulimia Nervosa or Binge Eating Disorder (DSM-5/ICD-11)
• BMI between ≥ 27 and < 40

Exclusion Criteria:

• Diagnosis of psychosis, bipolar disorder or substance abuse dependence and/or a high level of suicide risk.
• Use of weight loss medication or medications that interfere with appetite.
• Cushing or Prader-Willi syndromes
• History of bariatric surgery
• Patients who are already in treatment