Definitely cut weight, and it's more than water. 20-25 lbs is about the average. With the new 9am weigh-ins (weigh-ins on tv are for show) most fighters are gaining 12-15 pounds back easily, and all the ones I know say it's the best they've ever felt. Weight cut starts about 2-3 weeks out if done right and only needing to shed the last 2-3 lbs tops within 24 hours of official weigh-in.