Depends what plan you're on really. I'm doing All About W8 and we're allowed half a pint of skimmed milk per day for our tea/coffee and it hasn't put me out of ketosis. I've lost 20lbs and 5 waist inches in 4 weeks, and that's a good enough result for me. Who knows if I would have lost more, but being able to have teas and coffees throughout the day makes things more manageable.
I do Val, I feel fantastic though its not been all sailing theres been tears and tantrums along the way Family life has to go on and being on VLCD is hard when everyone around you wants Pizza Hut and Frankie & Bennies etc!!
Im determined this time though so i do feel i can do it!!