It does indeed. It's designed in such a way that all of this is optional. You can eat, but don't need to, or sleep, and still don't need to, these are just ways to fill your meters or skip time. There is a body weight mechanic, and I have been 'underweight' pretty much the whole time, but no hunger mechanic. So for those that want to live the life, there are lots of options, and for those who couldn't care less, they can ignore it entirely as long as the health, stamina and Dead-Eye meters are maintained. Pretty tight design if you ask me, leaving the importance of all these options up to each player, and never forcing any 'realism' stuff on you. Even the most important things, like being dressed for the weather, aren't terribly punishing. But you'll still be changing your clothes regularly as you explore the map. By designing it this way, R* has made it so it will appeal to all sorts of players with plenty of latitude on how each player approaches it.

I've managed to reach chapter 3, when the gang wore out our welcome and needed to pick up stakes and move down the road a spell. Bought a new horse, a brindle thoroughbred at the Strawberry stables which unlocked for the new chapter. I have a good warhorse, but wanted something faster too. Just need to bond with this one. I wanted a good getaway ride, some of the lawmen have fast horses no doubt. Bought a bandolier, and lots of improved ammunition. Obtained a Lancaster repeater through the story and it's the first gun I upgraded significantly, with the accuracy and range upgrades (sights and scope) and plan to use it often. There is plenty to spend your money on in this game, but I haven't felt the need to buy any guns.