I did a caring job for a little while - with home visits. It sure does open your eyes to things. On top of all the physical pain and suffering that those people have to go through, there's the depression and then sometimes the difficulties of the relationship with the long suffering home carer. Its Definiltey worth avoiding ending up in a similar situation.
Resolving pain like sciatica and joint pain is an excellent reason to lose weight.
I can certainly confirm that hot spicy foods makes you eat less. But i am not sure if it could really work as a diet food. I mean if the sensation of chilli pain is so unpleasant you will stop going towards those spicy curries. And if its not so painfully spicy, you will be able to eat everything on your plate quite easily.
I've done a few trips to india and the chilli nearly killed me - not really. But it actually depress me because i couldn't find anything else to eat that was nutritious sometimes in some of the places where i was. The only alternative was cake - which wasn't very good, and ice-cream which was. And i didn't lose weight because i was avoiding real food and eating the horrible stuff. But its true that spicy food does seem to make you feel like you can't eat anymore. But i think you've got to experience the pain to feel like that.