Okay I’ll hop on this train:
Neither, for a couple of reasons –
So like Chris Evans as Cap is probably doing a lot of bodybuilding-type exercises and eating to get the max amount of bulk in the shortest possible time – heavy-ass weights, low reps. Food-wise, he’d be consuming a shit ton of calories and low-fat protein (which he talks about, plain chicken and rice and being full all the time), and in the movie we see him extra-bulky because he’s also working out between shots to be swole. The dorito-waist is likely a combination of him being 6′ tall and definitely skipping leg day (comparatively speaking). I wouldn’t be surprised if they had him train that way on purpose just for contrast to emphasize the beefiness of his upper body.
Then if we take a look at Tom Hardy, we’ve got a completely different build – as Bane, or even as Charles Bronson, he’s projecting power because my dude is just large, but he’s not cut at all and some of the bulk is definitely due to a higher percentage of body fat. It works on him. I think part of the reason is that he’s not super tall (5′ 9″), but he is broad-chested and you get the sense that he could pound the shit out of you. In terms of eating/working out, he talks about it in this article re: Bronson, but I expect the same would be true for prepping for Bane:
I had five weeks to make the transition into Britain’s most dangerous criminal and it was a race against the clock: We didn’t have any time to waste, so I started eating and my arse very quickly got very fat. For Bronson, I put on about 7lbs a week — with no steroids. In the end I’d put on about 2 and a half stone by eating chicken and rice, which was my staple diet throughout the day. Then I’d have a pizza, Häagen-Dazs and Coca-Cola: So not good stuff, but I had to put weight on. I needed to put a layer of fat on my body, because Bronson when he was younger was a big guy, a brawler.
In the same article, he also talks about doing lots of reps and what sounds like bodyweight resistance exercises to build dense muscle (as opposed to bulk).
Now let’s talk about Shiro.
I’d argue the biggest factor in Shiro’s post-Galra physique is likely nutrition. Now obviously we don’t have much from canon to go on, but as a slave, especially before he becomes Champion, there’s no way the Galran Empire is going to be spending the extra money/resources/time to make sure he’s well fed. From what we see of the arena, a lot of the beings sent in to “fight” are really just bodies for the more successful fighters to cut down, so in the eyes of the Empire, not worth much investment.
In terms of quality of food, there’s the question of how well Galra slave fare is going to actually feed Shiro from a nutrition standpoint. Like do they have different formulations for different races? Do they just feed everyone the same things and hope for th best? (these are the questions that keep me up at night). Without going too far down the road of speculatory xenomorphology? xenophysiology?, it wouldn’t make sense for beings from all corners of the known universe to have similar chemical cycles to a human’s. If we average the possibilities (perfectly formulated nutritive substances vs. bottom-of-the-barrel prisoner fare), I think it’s likely to be somewhere in the middle.
There’s also the question of quantity. Is the Empire feeding their gladiators a ton of shitty food? As little food as possible? It would make sense that the quality would increase as a gladiator survived more fights (signaling a more worthwhile investment from the entertainment and possibly product/merchandising standpoint), but even still I can’t imagine Shiro getting much beyond the bare requirements in the beginning.
All that said, I think it’s safe to say that for most, if not all, of Shiro’s Fun Year™, my dude was not getting the best grub, and definitely not the kind of high-quality/quantity protein required to get Real Big.
Then from a physical activity standpoint, it’s hard to say what he was doing outside the arena, but certainly surviving many multi-creature encounters would require a literally impossible ton of stamina, which means an unbelievable amount of cardio, which again is not the path to being Real Big. Plus like idk where he’d be lifting a ton of weights. We can assume that no one would stop him from working out in whatever cell or quarters he was kept in, but bodyweight exercises are better for strength than bulk. Plus our dude is tall.
Which means a lot of his key muscle groups are going to be longer so even if he were Big it would be more distributed than you might expect when he’s standing relaxed. You also have to remember that the suits add a significant amount of bulk, especially in the back/shoulders.
Here’s a good ref for immediately post-Galra Shiro:
Fanonically speaking, Shiro tends to get portrayed as somewhat bara, but if we look at him here, yeah he’s got pretty clearly defined muscles but he’s not gigantic. I’d guess his upper arms are particularly pronounced from (1) wielding weapons in the arena (as we see in flashbacks) and (2) later from lugging his gotdamn metal arm around, but again they’re not bulky, which makes sense given the likely nutritional/fitness situation one would be in as a gladiator/slave to an alien empire.
In conclusion, Shiro has a fighter’s body, more along the lines of what you’d expect from someone who does MMA, jiu jitsu, or boxing, with maybe a side of sprinting in there for getting away from giant Robeasts. MMA is probably the closest thing we have on Earth to a gladiatorial sport, so it makes sense.
Shiro is naturally tall and actually fairly slim; you can’t exercise your way to a waist that waspish if you don’t have a narrow-ish pelvis. He’s got long arms (which would be v. good for reach both armed and unarmed) and long legs. Picture that kid in his early teens with limbs for days and no idea where to put them. Probably by the time he got to the Garrison or while at the Garrison, he started putting on some muscle. I wouldn’t be surprised if he focused more on cardio in terms of leg exercises, but that definitely would have changed once he was captured; those are some well-toned thighs. Even Ulaz appreciates them.
From an artistic reference standpoint, I’d recommend checking out middleweight UFC fighters who are over 6′ (link is sorted by height). Just look at the top 5 dudes and you’ll see what I mean.
This concludes your Shiro anatomy lesson of the day. Thank you for your time.
