I know that your weight affects how much you can wear for free. You get 10% of your weight in free wearables (as in, no penalty). So a 220 pound Kaumo can wear 22 pounds of armor, and if he's carrying nothing else, he has 0% penalty. Essentially, as far as I know, weight is only ever a good thing. Although now that ice breaking is in, maybe a heavier character is more likely to fall through the ice?
I'm currently running my most successful character ever. A 228 lb, 6'3" kaumo with decent stats, 73 bow and spear skills, and very good speed and endurance. He walks at 7mph unburdened, so I can tire out big game fairly quickly when hunting.
Still, I had a very tough time starting out, because I picked the advanced game course, and the abandoned camp start, meaning while I started with a couple free tools and weapons (nothing great though, just a battleaxe and a small trident) I did not start with a fishing pole. So I nearly starved early on trying to fish with my trident. Luckily, I did put some starting points into fishing, and managed to survive on what little I could catch along with some bird and squirrel meat until I spotted an elk in a wide open mire, and chased him down. Of course, I didn't have a cellar or a hut yet, so while I had lots of meat, after a short time I had lots of spoiled meat.
It's silly that you can survive so well off spoiled meat. Sure, you throw up a lot, and get some minor injury, but it goes away really fast (maybe my endurance helped here?). I was able to live off spoiled meat and some occasional berries and small game quite comfortably...
The part of the course I was on required me to build a trap fence, so I built a very long fence in the mire, with some gaps for pit traps. Imagine my distress when I found out you can't dig holes in the mire!
So I moved my trap fence into the nearby woods, using the trees to help extend it, and dug some holes, throwing up my spoiled food all over the woods. After I was satisfied with the fence (it was about 3 fully zoomed out screens long) I went on a hunting and berry picking expedition, took down some small game, returned home to cook it, and found a stag in a pit! After that point, I was pretty well set, and dug out a cellar to preserve my food a bit longer. Things just got better and better from there.
At this point, it's just after the middle of winter (I think). I have probably 2000 lbs of dried meat, a HUMONGOUS pile of weapons and clothing I liberated from the Njerpez... and some lonely vagabond woodsmen... I just took out a Njerpez village (Although I got an arrow through the neck in the process). I am currently trying to cure my massive neck wound, so I can go back out and continue cleaning Finland of the horrible Njerpez slavers.
It's looking like I might actually survive an entire year, although I suppose I'm always just a lucky bowshot away from death messing with the njerps.