If there's not enough available to make it through the winter to spring, just don't get started on it.
The problem with eating same species is that you absoarb a small amount of genetic material into your own makeup. When you absoard too much material that is too similar, you get what I can't describe more accurately then a genetic feedback effect. A little wont hurt anything, but frequent cannibalism will cause health issues.
Ketchup of course, everything is better with ketchup. Time for another bowl of vanilla ice cream and ketchup
The real question is, do you kill your buddy on day one while he's still nice and plump, stuff his body in the snow and eat him all winter long, or wait til you're both skin and bones and theres nothing left of him to eat?
Do you draw short straws or just kill and eat the fattest? As a thin person I know which side I fall on.
Also I can maybe recover the fat to make a "Lard" I mean if you're going to have long pig bacon it has to be fried
if you're starving and need to resort to this it's likely the person you're eating likely died of starvation and that case it'll do you more harm than good as they don't have any fat, the remaining bits will burn more calories in digestion than you gain. So no I wouldn't do it. There's not much point to it unless you're planning to murder healthy people and eat them and I wouldn't do that either.
tens of millions have died from starvation without resorting to cannibalism, so you're wrong only a very tiny, tiny minority would.