Despite the societal impact of eating disorders, the exploration of mobile apps for eating disorders and in particular their AI-based features has been limited. We report a functionality review of 4 apps for eating disorders which claim to leverage AI. Findings indicate that apps provide functionalities such as tracking of thoughts and moods, and provision of interventions, including conversational agents designed by using ML and NLP, albeit the specific use of AI lacks clarity. We advance some heuristics for AI-based mobile apps for eating disorders which, by drawing from previous work, we grouped under four themes of heuristics for decision-making, personalization, productivity, and security.