Another idea that's been hanging around in my mind. This would be a prologue.
Everybody in Konoha knows of the Kyuubi incident seven years ago, when the Nine-Tailed Fox attacked their village, and their Fourth Hokage died defeating it. But not all of them know that the Kyuubi could not be killed, only sealed away. In this case, it was sealed in the body of one Uzumaki Naruto. However, the hatred left in those who survived while their friends and family members did not was not easily erased, and its bearers treated the child with contempt. In order to protect the child, the Third Hokage (Sandaime Hokage) passed a law banning anyone from talking about the Kyuubi's sealing. But the adults inadvertently influenced their children to shun the boy as well, and Naruto grew up lonely.
But in some cases, the hatred manifested in the form of attacks upon the young boy, which was why on this October tenth, Naruto could be found fleeing the mob that was after him crying for his blood. He was running as hard as he could, trying to stay in front of them, only the barest of thoughts spared for wondering why he was being treated like this. Even though he could hardly hear them, Naruto knew what the screams were saying.
"Kill the demon!"
"Make it suffer!"
He didn't understand why they called him a demon. He was just a child! Naruto just kept running and running, seeking a place where he could hide safely.
Then suddenly, as he was running down another alleyway, Naruto tripped over something. But when he picked himself up for a look, he saw that there was nothing there. However, on second look, he saw a trapdoor; he had tripped over the handle.
There wasn't any time for him to question why the trapdoor had somehow appeared out of nowhere, as the mob was drawing closer. Naruto barely hesitated before pulling the trapdoor open and sliding through the opening, closing it after him.
In the darkness, he realized he was in a vertical shaft, his foot balanced on the rung of a ladder. Hearing the muted cries of the people that were after him, he decided that he had no other way to go but down. Groping around, he found purchase for his hands, and began to descend.
Naruto had no idea how long he spent climbing down, but eventually he reached the bottom, which was just as dark as everything. He could tell by the feeling of the rungs beneath his fingers that no one had been in this place for a very long time; there was a thick layer of dust that filled the air with his every movement, forcing him to breathe lightly. Feeling in the dark to make sure he wasn't going to run into a wall, he followed the passage he found himself in, until he saw a dim light. Feeling encouraged, Naruto rushed towards it, and emerged into a place that went beyond anything he could imagine.
Various glass jars were stacked on shelves lining the walls, all containing various plants and creatures suspended in liquid. There were also test tubes in racks and various types of lab equipment, as well as several books of varying thickness. Like before, everything was covered in a thick layer of dust. The light he had seen came from a dimly glowing bulb hanging from the ceiling, but the moment he stepped across the threshold of the room, it brightened, making him flinch back in fear.
After a few minutes, when it was clear that nothing else was going to happen, Naruto gathered up the courage to venture further into the room. Bit by bit he grew bolder as his curiosity overcame his nervousness, and he began poking around. There were so many things in this room, but he had no idea how they worked, just that they were fun to play around with, twisting knobs and flicking switches.
Until he accidentally bumped a table too hard, and one of the jars tipped over to fall on him.
"AAAAH!" Naruto screamed when it broke over his head, dropping its inhabitant on top of him. "Getitoffgetitoffgetitoff!"
It was wet and slimy, and it had long tentacles that wrapped around him. Out of desperation, Naruto opened his mouth and bit the body hard, severing the portion in his mouth from the rest of it. Then his eyes widened; the thing was DELICIOUS! The run from the mob had left him with a powerful hunger, and before he realized it, he was devouring the organism.
It was a jellyfish, but Naruto never knew it, because he had never seen one before, as Konoha was far from the sea, and he was never allowed to enter the library. He also didn't noticed that it regenerated slightly in its wounded areas, but not fast enough to match his eating. Still, it generated enough to fill his small stomach by the time he finished every bit of it, not caring if it picked dust off the floor or had been soaking in some unknown liquid for God knows how long.
But he soon started regretting it when pain wracked his body. To Naruto, it felt as though something was tearing his body apart and putting it back together repeatedly. He had no idea that the cells from the jellyfish were implanting themselves into his body, transforming him into something never seen before in the ninja world.
In a pocket dimension formed by the seal on his body, the Kyuubi perked up, sensing its host was in a dangerous situation. It could tell because the slow drain on its chakra reserves had suddenly jumped up a thousandfold. Snorting, it rammed even more chakra into the flow, hoping that it would overload the channel and break the seal.
Unfortunately, it did not work, and the Kyuubi settled back down grumpily. It would eventually get used to the adjusted drain, but it wondered what was happening outside.
Naruto's thrashing knocked a pile of books off its table and onto him, and one particularly heavy tome slammed into his head and knocked him into blissful unconsciousness.
Sarutobi Hiruzen, the Sandaime, was worried about his young charge Uzumaki Naruto. No one had seen him for the past week already, and he feared for the young child. Even his treasured crystal ball refused to show any clue to Naruto's location. He was on the verge of giving up when one of his ANBU guards appeared.
"Hokage-sama, we've found Uzumaki Naruto."
Hiruzen bolted upright. "Where did you find him?" He demanded.
"He was found wandering in the alleys, covered in dust and grime. He is currently recovering in the hospital."
"Let's go."
The Hokage immediately Shunshin-ed (Body Flicker) to the hospital with the ANBU accompanying him. There, he was informed by the doctors that they were currently running tests on the boy, who had been changed somehow.
"Changed?" He queried.
"What we've found out so far is that his cellular regeneration have increased beyond what it was before. We suspect his..." The medic that was assigned to answer questions paused to think of a term that wouldn't violate the law set by the Sandaime. "Acquaintance... has modified his body."
Hiruzen stared at the man, waiting for him to add what he wasn't saying.
"Except we haven't found any trace of its chakra. Uzumaki seems to have achieved this change without it."
"Where was he found?" Hiruzen asked.
"An ANBU found him wandering the alleyways. He was in an extremely filthy condition, but unhurt."
"The sewers?"
The medic shook his head. "No. There wasn't any feces on him, just a large amount of dust."
A frown crossed the Sandaime's features. "Did he say where he was?"
"He does not know." The medic paused again, but this time as though nervous to say what was coming next. "But we believe he found his way into one of Orochimaru's hidden labs."
Hiruzen paled. The thought of the innocent child discovering one of his former student's den of human experimentation was a horrifying one. "God! Where was it?"
"We do not know. Uzumaki is unsure of the location."
"What did Naruto do there?"
"According to him, he ate something that was in a storage jar." The medic looked revolted at the thought of anyone doing that, and Hiruzen paled even further. "It could be the reason for his current change."
"That Orochimaru..." Hiruzen growled. "What else did he say?"
"He said it made his body experience intense pain, which was why he didn't eat anything else."
"Good." The old man paused when something about that statement bothered him. "...wait, nothing else?"
"That's what he said, Hokage-sama."
"That means he didn't eat anything for nearly a full week!"
The medic paused. "But according to our examination, he wasn't experiencing starvation at all."
"What has happened to you, Naruto?" The Hokage asked no one in particular.
His companion coughed. "Oh, and Uzumaki also has a book which he absolutely refuses to let go of."
"A book?" Hiruzen was curious.
"Yes, Hokage-sama. Could you get him to release it to us? It might hold a clue to what happened to him."
It would be another hour before the doctors were finally finished with Naruto. When they reported their findings to the Hokage, it was astounding. The boy's body was found to contain a new cell type never before encountered. It was responsible for his enhanced condition and regeneration ability, but it also had a high energy demand, something which was offset by the chakra of the Kyuubi. As things were now, Naruto would experience a greatly increased appetite in order to make up the difference.
When Hiruzen entered the ward Naruto was in, he was surprised to find the boy just as lively as he recalled. Except that Naruto was reading, something which he never did willingly before.
"Jii-chan! You never believe what I found!"
"What is it, Naruto-kun?"
Naruto brandished the book in his hand for the Hokage to see. "This great storybook!"
The title of the book was 'The Four Heavenly Kings of Gourmet', and Hiruzen felt slightly disappointed to find that it didn't contain any medical research at all, but was just a storybook.
But he had no idea that the future of Naruto would be shaped by the tales in that book.
On Naruto's part, he eventually recalled where the secret entrance of the hidden lab was, but he would return there many times in the future without telling anyone, in order to sate his curiosity about what was hidden within. For some reason he would not know until later, he was the only one who could find that trapdoor. And with the secrets hidden beneath it, Naruto would bring about an unexpected revolution in the ninja world.
In time, many people would know the legend of Uzumaki Naruto, the Gourmet Shinobi!
So that's how I would start a Naruto/Toriko crossover. Naruto will have the abilities of the four, Toriko, Coco, Sani, and Zebra, but since he's distributed across them, he won't be able to match their levels so quickly. Naruto will also teach himself to revive ingredients and cook them, and eventually discover more hidden labs with further ingredients to revive and cook.
In such a case, I don't think he should learn Kage Bunshin, but Naruto without Kage Bunshin is... well, I suppose I would need to read more fanfics of that setting. In any case, please give me feedback on this, and tell me if you think I should continue with this one-shot.