My bike gets weighed when I fly on an airplane so my "common practice" is to weigh the bike along with the enclosing box - and weigh the gear together with a duffel bag and pedals/saddle. I don't fly with water so that isn't included. Food was weighed when I flew to Prudhoe Bay but otherwise I buy food at the destination and don't fly with it. In general the goal is to keep both the gear duffel and the bike box less than 50 lbs to avoid over-weight fees.
Other than flying I haven't worried much about weighing the bike.
Water is also rather variable depending on where I am going - so I worry more about what are the longest gaps between water stops and if those are more than a day apart what containers do I have to carry water.