Thompson had Prader Willi Syndrome, whose sufferers are affected by obsessive eating and learning difficulties.
Thompson died about three hours after arriving there by ambulance with stomach pain and vomiting.
The night before he obtained keys to the Idea Services home's food stores and "gorged himself on a large quantity of food". In medical terms, "massive acute consumption of food" was one of the main reasons he died.
He is believed to have eaten three loaves of bread, eight buns and 24 muesli bars.
That night he suffered from what care worker Tia Taukamoa described as an "upset tummy" and he "messed himself" constantly in bed and in the hallway.
Usually he would say if he felt sick but that night he didn't.
About 4am Ms Taukamoa found a set of keys to where food was kept hidden under Mr Thompson's mattress. She checked but wasn't sure if any food was missing. Mr Thompson said he stole the keys from the office.
For breakfast, Mr Thompson had fruit toast and milo as usual, but he didn't finish his muesli.
A search of his room by another care worker, Angela Harmer, soon revealed a bag of hamburger buns with eight missing, 24 empty muesli bar wrappers and three empty bread bags.
Mr Thompson went about his normal routine and although he was "burping and farting and had a bloated stomach", this was thought normal after he had extra food.
But when he arrived at his community programme that morning Mr Thompson was struggling to walk and "sort of waddling". "[Community service worker Karen Brookes] recalled his stomach was huge, that it sounded as though he was having trouble breathing, and this his face was pale."
He was taken to a doctor and when his stomach pain and vomiting got worse, to hospital.
Coroner na Nagara said Mr Thompson's condition worsened on Ms Taukamoa's watch and while she clearly was concerned about him and helped him appropriately, she wasn't proactive enough once she found the food keys.
Idea Services workers also failed to effectively tell medics how much food Mr Thompson has eaten and when he'd done so, although the coroner also said she didn't intend any "personal criticism of individual workers as there is no evidence anyone was less than committed to discharging their responsibilities adequately".
Rather, it was a "training issue" and Coroner na Nagara recommended that Idea Services review and deal with the issues raised over Mr Thompson's death and possibly provide staff with more training.