I love training too, have been doing it for more than half my life. Sometimes though I just have a hard time getting back into it after a lay off.
The diet problem is more about not knowing as opposed to eating a lot. If I am on vacation or have a friend visiting we eat out most meals, which for me is twice a day. That does not necessarily mean I will eat a lot. But without fail it will take me a few days afterwards to get back in the habit of making my own meals instead of eating out.
Basically, if I take a break of a few days for whatever reason I need to get that break to stick to just those few days and not let it linger a few more until I am back to normal.