It wasn't a food thing, exactly. Not in the beginning. It was a control thing.
Sam had never had control over his life- he was expected to comply to everything John expected of him, and even after his father was gone, he was expected to continue following in his footsteps.
It was his job, his duty, his life.
And he had never had any choice in it. He had a choice in what he ate, though. Out of every controlled and limited part of his life, eating was really and completely his.
Dean saw it as him being a health nut, at first. He started ordering salads and light soups instead of the hardier, greasier meals he had grown up with.
'Rabbit food', Dean called it. And it was a joke, at first, that Sam 'cared about maintaining his boyish figure', or jabs to that effect.
When calories were listed on menus, Sam slowly got in the habit of picking the lowest number. He reasoned it away with the fact that since they ate so unhealthily most of the time, he might as well make some effort.
That was at first. Limiting himself a little, trying out something new with cutting down how much he ate just a little each day. He reasoned it away with it being 'healthier', but about a year later it became clear that that simply wasn't the case anymore.
Sam had stopped eating breakfast first, switching to just a cup of coffee or tea to give him a caffeine kick. That was easy- he was never really hungry in the mornings anyway, and he reasoned that he shouldn't eat if he wasn't hungry.
Dean commented on that a couple of times, but didn't seem concerned; Sam was still on top of his game and hadn't visibly lost weight or been affected by the change, so it was fine. Anyway, there were demons to exorcise and werewolves to track down and vampires to behead. No reason to worry about such a little change when so many bigger things were always happening.
Lunch was next to go- At midday, Sam was generally so immersed in research or a case or doing something that he forced food to the back of his mind. It was easier. More efficient. It was a waste of precious time that Sam slowly saw as less and less necessary. And with the bunker as large as it was, it was disturbingly easy to lie and say he'd had a snack in his room, or even that he and Dean just hadn't been in the kitchen at the same time, but yes, of course he'd eaten.
If he remembered, he'd have an apple or something in the early afternoon. If he remembered. As time went on, that became less and less frequent as well.
By the end of the day, Sam's stomach had usually become tight with hunger. He and Dean usually ate together, though, meaning that he had to force something into his system in order to keep Dean from catching on and nagging him about his eating habits. He knew, somewhere in the back of his mind, that if he was keeping it from Dean, it was a bigger problem than he thought.
But he couldn't bring himself to care.
The last thing to go was dinner. Or rather, he didn't completely stop eating it, but he ate less. And less. First a bite or two would remain, then a third of his food, then after about a month Sam was consistently eating about half of his dinner. And that was it, for the entire day.
At that point, Dean caught on that something was wrong.
"Finish your food." Sam didn't look up from his picked- apart bowl of stir-fry.
"I'm not five, Dean. You don't exactly need to tell me to finish my vegetables." Sam's voice was falsely calm, barely covering his sudden panic at having been discovered. It had been so long since his issue with food had begun, that he had somehow deluded himself into believing that he was an expert at hiding it.
"I'm not saying to finish your vegetables. You ate the vegetables. And that's all you ate." Sam looked closer at the contents of his bowl to discover that Dean was in fact right. His rice was smashed to teriyaki-sauce-colored mush, mixed with the shredded and completely destroyed bits of chicken he had been painstakingly tearing apart with his fork for the past twenty minutes.
"I had a big snack earlier." Sam mumbled, stabbing again at the repulsing, ground-up food. "'m not hungry."
"You didn't. And you know how I know that?" Dean waited for a response, so Sam shook his head, "because I was in the kitchen all day. All day yesterday, too. And you know where you never were in the past two days?" Sam shrugged, bracing himself for the inevitable verbal attack that was soon to come. "The kitchen. You haven't been eating, Sammy." When Dean didn't keep talking, Sam looked up to measure his reaction. His brother looked uncertain, uncomfortable, pained by the conversation.
"I'm fine, Dean." Sam muttered before getting up and clearing his bowl to the sink, leaving before Dean could say another word. Dean didn't try to follow him or press the subject or start an argument, and for that, Sam was grateful. Sam retreated to his room, mind overflowing with too many thoughts.
Rather than taking a seat at the desk or even on his bed, Sam sat with his back to the door and knees drawn up to his chest. It was a vulnerable position, but he was safe at the moment, safe from everything but the thoughts in his own head.
Don't you see how stupid this is? How stupid it was from the very beginning? How obvious it was going to be? What are you gaining from this, anyway? Do you want to die of starvation? Of all the ways for a hunter to go, that would be the most pathetic.
Sam took a deep breath and readjusted his sitting position on the floor, trying to get comfortable. He hadn't really noticed how much weight he had lost until then- but the fact that he couldn't even sit comfortably on the floor was a pretty big indicator.
Sam's breath hitched, fighting back the tightness in his throat that could mean oncoming tears. He tightened his arms where they were wrapped around his knees, feeling more sharp angles and less firm muscle than he ever had before.
He'd been a chubby baby, a pudgy teenager, and since then had rather a lot of muscle, as came with the job. He'd never been thin, or even particularly thin.
Sam decided that he had been ignoring the damage he had been doing for long enough. He pulled himself up from the floor, crossing the room to the full-length mirror in the corner. He examined his face first- he knew there were changes there, but hadn't known to what extent until then.
There were dark circles under his eyes, more pronounced than they had ever been even at the heart of a case. His features looked sharp and exaggerated, like an artist had come along with a pencil and shaded his face with twice as much shadow and contrast as usual.
After a minute, Sam pulled off his flannel, exposing his arms. They had lost the bulk of their muscle, and though they were still far from being sticks, Sam felt like he could snap the bones if he tried.
When he pulled off his shirt, baring his chest, he looked downright emaciated. He had never been able to see his ribs before- not so clearly as he could now, anyway. If he lifted his arms above his head, he could clearly count them all. His stomach was nearly flat, and had lost most of the muscle tone it usually had.
It was to that scene that Dean entered the room, a minute or so later; Sam standing shirtless before the mirror, staring at his own bony reflection as though in a trance.
"Sammy?" Sam jerked out of his thoughts and practically dove for his shirt. "Hey, it's okay, man, relax." Dean waited as Sam pulled back on his shirt and flannel, as though covering up would hide the sight of the damage that had been done.
When Sam finally turned to him, it was with a look of shame on his face. "Sam, listen. You know this is a problem, right?" Sam nodded, a movement so small that it could have been missed if all of Dean's attention wasn't focused on Sam. "See? That's the first step. We can fix this, Sam. And I will help you." Dean held out the cup he was carrying, and Sam took it, curious as to what Dean would have put in a pink plastic cup with a curly straw.
"It's a smoothie. Just fruit and a little juice and ice, no milk or anything. And you're going to drink it-" Sam's eyes bugged in fear in a way that made Dean's heart ache- How had he not noticed his little brother was so sick?
"Dean, I-" Sam looked down into the cup again, and his stomach twisted in fear.
"Not the whole thing, if you can't. Just… as much as you can. C'mon, Sammy." The image of how thin, how weak, how vulnerable Sam looked was still burned into Dean's mind.
"… Fine." Sam sighed, steeling himself for the food. He didn't want to drink the smoothie, every reflex was telling him not to. But Sam was nothing if not determined, and no matter how much he hated the idea of it, he knew he had no choice. The logical part of him told him that this was a stupid thing to work himself up about, but his state of mind was so screwed up that he couldn't help it.
He brought the straw to his mouth and took a small sip, forcing himself to drink it despite his body's protests.
Dean, forcedly casual, took a seat on Sam's bed. "You remember that one time when I was ten and you were… six? Like, the year when Dad finally decided we were old enough to be left alone?" Sam shrugged.
"There was the time we walked to the dump at midnight because you thought we were on a ghost hunt." Sam could tell Dean was just trying to distract him, but he didn't mind, and actually welcomed the memories to focus on instead. "It was before I knew about monsters and stuff, so I thought you were just trying to scare me."
"Yeah, and you thought I was bringing salt because we were going to season up and eat the food in the garbage once we were done-" Dean winced, realizing that a distraction regarding disgusting, thrown-away food was probably not the best idea at the moment.
"And you fell and scraped your knee and said 'the ghost' tripped you." Sam's voice was tense as he forced a slight subject change.
"Y'know, I think that was the first time we went hunting together, Sammy," Dean teased, "Even though the 'ghost' was actually just the old guy who owned the dump." Sam had stopped drinking his smoothie and was stirring it with his straw, pensively.
"Yeah, I guess it was." Sam's mouth curled up in the barest attempt at a smile. His words sounded strained, though, and Dean put a hand on his shoulder in concern.
"You okay?" he asked. Sam nodded quickly- too quickly. "Really, man, what's wrong?"
"Just… been a while since I ate so much, 'm feeling a little sick." Dean looked over to see that Sam's cup was still two-thirds full. He took the cup from his brother's hand and reached over to place it on the nightstand.
"Then that's all you need to drink right now, don't make yourself sick, okay?" Sam nodded again, and Dean moved his arm to Sam's other shoulder, wrapping it over him protectively.
"I'm good. But, ah…" Sam's eyes flitted around the room, carefully avoiding Dean. "Sorry… 'bout this. 'M sure you had better things to do than worrying about me." Dean pulled Sam closer, into a tight one-armed hug.
"Don't say that, Sam. You're…" Dean picked out his words carefully, not wanting to say 'sick' or 'struggling' or anything that might imply weakness, "You hit a rough spot and I'm here to help you with it. Whatever I can do to help you, I'll do. Just don't apologize for needing to lean on someone every now and then- if not for stuff like this, what are brothers for?"
Sam nodded, his eyes finishing their millionth sweep over the room to land on Dean's face, finally. "Thanks, De. For, ah… For everything."
The problem of Sam's eating habits was far from solved- it would be a long road, but Dean had confidence that his brother could do this. It would just take small steps and plenty of support and encouragement, both of which Dean hoped he was capable of giving. His brother had saved the entire world from the apocalypse, Dean had no doubt that this issue would not be the cause of his brother's downfall.