I find it hard in the winter as well, but it's not with the fluid intake - I've always drunk loads so don't find that a problem.
For me, it's when it's cold, wet and horrible out I prefer to eat what I call 'comfort food', lots of warm, filling food - baked potatoes, cheesy-onion mashed potatoes, cheesy vegetable bakes. And these things don't figure much in Detox's.