I think its generally a bad idea to put too much effort in to restricting ones diet - unless there's a firm reason for doing so.
Caffeine sends me nuts, so I avoid that. I'm generally low sugar, and try to eat healthily. I react a bit badly to too much gluten and dairy, so try to be aware of that, and not have too much - but cutting things like that out totally seems more trouble than it's worth for me. With often being too tired to cook, it's easy to fall back on too much gluten (pasta, bread, etc) because it's easy - so I try to avoid it when I'm feeling well enough to cook properly, and then have it as a reserve for particularly tired days.
Because we're all ill and desperate to get better, and food is something we're all aware of putting in to our bodies, I think it's easy to go a bit paranoid about it, and start feeling like their must be some 'perfect diet' to be found which will help, when often there's not.
(That's not to say that some of you won't be genuinely badly affected by certain foods - just that I think it's easy for us to all exaggerate their significance if we're not careful. I think some can be far too dismissive of the impact different foods can have on different people, and some can be far too committed to rather ritualistic diets - I try to take a lazy middle route).