So let's take on Wolverine and Deadpool one at a time. We'll begin with Wolverine. Wolverine CAN starve. He DOES need to eat.
Technically, yes. Wolverine should not be able to survive without food. It is estimated that a human cannot survive for more than 45 to 61 days. However, writers have made wolverine just short of being immortal.
If Wolverine were to stop eating, there would probably come a time when his body could no longer maintain his healing factor, which would be rendered incapable of repairing the damage he does to himself by not eating. Beyond a certain height –the structure can't sustain the weight of a man 5 times the size of normal.
The short answer is yes, Wolverine can die and has many times in the comic books.
Wolverine Gets Torn in Half by the Hulk
Wolverine #1, the Hulk wasted little time before ripping Wolverine in two and tossing each half of his body in different directions. To survive, Wolverine's top half had to literally crawl until he located the bottom half and let his body come back from that one.
So while the bullet might penetrate Wolverine's skin, it seems it wouldn't kill him. In fact, in X-Men Origins: Wolverine, Wolverine is shot in the head with an adamantium bullet and, though he loses his memory, he survives.
The doctor notes that “something inside” Logan is “poisoning him.” Logan responds by saying he knows what it is inside him that's killing him. Adamantium poisoning as a reason for Logan's diminished healing factor works well with the themes in “Logan.” The movie is about finality and, often, despair.
However, Deadpool's healing factor goes a fair bit beyond Wolverine's, in that Deadpool's healing factor essentially prevents him from dying unless it is something catastrophic. Typically speaking, if Wolverine had an arm chopped off, he would not re-grow a new arm. Deadpool's powers do, in fact, do that.
LIFE CYCLE: Wolverines are thought to live about 10 years in the wild. FEEDING: Wolverines are scavenger-predators that eat carrion — mostly sheep, caribou, and moose — and small mammals, including porcupines, squirrels, beavers, and rabbits. Wolverines have been observed killing large animals like caribou and deer.
While that is his main weakness, Logan has died by having all his flesh melted off his body, by suffocating in adamantium, and he even killed himself once to end a threat to the world.
Foreign Chemical Immunity: Wolverine's natural healing also affords him the virtual immunity to poisons and most drugs, except in massive doses.
It's uncertain how long Wolverine, from Marvel Comics X-men, would live if he didn't have an adamantium coated skeleton. He could possibly be functionally immortal, with his healing factor halting his aging. Meaning that he could be killed, with great difficulty, but would not die from old age.
Being crushed by a train is just one of the crazy things Wolverine has survived. Wolverine has suffered more than probably any other superhero. He's been shot at, stabbed, eaten by a Tyrannosaur Rex, and sustained a thousand other injuries that would kill the average man.
He can't Starve to death. In one comic he was stuck under a fallen building (that's what I think it was), and he stayed alive in there for a long time. It was an alternate future scenario. Decapitate him and seal his head in a strong box.
In Wolverine #900, Logan revealed his healing factor processes alcohol nearly as quickly as he can drink it, with a bottle of whisky only getting him tipsy for seconds. It seems Wolverine is capable of getting drunk, but only for an extremely short amount of time (unless he has a constant supply of alcohol.)
If Wolverine or Hulk accidentally got bitten by a zombie, what would happen? Actually, nothing would happen! Their healing factor is too powerful.
Users. Wolverine: Because of his healing factor, Wolverine is able to live longer than normal and show no signs of aging until a later period of time. X-23: Being Wolverine's clone, X-23 possesses the same healing factor and therefore has the same ability.
However, yes, it would be technically impossible to regenerate from “nothing but his adamantium skeleton”. If every atom of his DNA was disintegrated it would not be technically possible for him to regenerate.
8 Wolverine: Stronger Healing Factor
Furthermore, his healing factor works even faster on extreme injuries, e.g. if large layers of flesh and muscle are lost. For all the damage Superman can do to him, there's always a chance Logan will get better.
The Flash's body heals at an accelerated rate and it registers the tattoo as damage which it quickly heals. Kid Flash's tattoo was gone in a few seconds because of his healing factor, yet when Wolverine got a tattoo, it took much longer for it to disappear due to his healing ability.
By and Large, the answer is Hulk. Wolverine's healing factor is amazing, one of the best in the business. There's a reason why people are always trying to compare his against others.
The primary reason why Wolverine is dying in 'Logan' is adamantium poisoning. Due to his old age, Wolverine's healing factor was not as effective as before, which resulted in adamantium slowly taking its toll on Logan's body.
Viper then tends to Yashida after Logan left. Later that night, Viper infected Logan by planting one of the parasitic robots; the nanobot latches itself onto Logan's heart, shutting down his healing factor and made Logan mortal.
During the final fight in The Wolverine, Logan-San had his adamantium claws sliced clean off by The Silver Samurai, leaving him with organic bone claws that grow back through the stubs of the adamantium coating.