I don't know. Foreman was just big, I don't see anything particularly unnatural about the way his arms and shoulders look. He might have taken steroids, but so might have Muhammad Ali or Emile Griffith or anyone. There's nothing in Foreman's physique to signal something chemically-enhanced though.
There was certainly stuff around in those days - that's when bodybuilders started getting freakishly big, although nothing compared to today - but early pictures of George, when there's no way he'd have had access to them, show a really muscular kid. Ditto Mike Tyson when he was a teenager (though I can see him taking them later in his career; he was looking a bit bloated in his last few fights, though that may have just been age and crappy training taking their toll). There's a tendency to automatically think steroids when we see a really muscular person - sometimes it's just that genetic crapshoot that blesses some more than others.
A few may have been on it. But in the early 70s the Russian amateurs were certainly doped. Late 60s was probably already the start of the steroid era for the olympics.
Steroids in sport became prevalent in the 1970s, and because there was no testing, the doses athletes took were huge and the steroids powerful. You just have to look at the 400m women's world record from that decade which still stands today, as evidence of this. So I would say the 1960s were pretty clean in all sports, but a decade later then we have to be more suspicious.
For Foreman it would have been suspicious if he was about 235-240 pounds with the same bf% he had in his title run. But he never was that, so his physique is no evidence. He didn't have other signs that may indicate steroid use and neither did he fail any tests.
Steroid testing didn't come about in major sports until after the Ben Johnson scandal in the 80s. The Chargers in the NFL were all on dbol by the mid 60s because they had a strength coach with connections to US Olympic weight lifting. It isn't impossible but I would say he just has great Texas freaky athletic genetics.
I don't have eyewitness proof, if that's what you mean ... but given the circumstances of his background (poverty, Job Corps), I can't see where they would have come into play. If he had access to drugs on the streets of Houston in the '60s, steroids would have been pretty far down on the list ... there were more appealing options out there. Again, when you look at him back then, there's no crazy, exaggerated hypertrophy (think Barry Bonds, or even Evander who did have links to PEDs); just a big, strong kid.
I agree, there's nothing in his appearance that suggest anabolic steroids. But it's possible. It's possible steroids were on the streets of Houston, or around the gyms, youth clubs, sports teams, when Foreman was 15 or 16. And it's actually likely that there was some sort of steroid presence locally. It's more likely Foreman didn't take them though, back then at least, I agree. Tyson's another matter. He might well have been on PEDs from 13, since he was apparently being groomed to be a champion from that age.
How much effect would ol' classic steroids have without any weight training? It must have some I suppose, but do anyone know more specifically?
Steroids can make a significance difference without any training. Hence their medical usage. If you take them and limit your exercise to only hitting a heavy bag, you'll likely become a noticeably better puncher (produce more force) than if you just did the heavy bag and no steroids. Of course, different individuals respond differently to the same drugs, so there's a large area of uncertainty. But generally, steroids work. They work well.
As far as I've gathered steroids starting being widespread in bodybuilding in the 60's and in the Olympics in the 70's. Bxoing has always been a traditional sport and a bit slow on the uptake on new trends but at least by the 80's and 90's it should have come in to the sport. It's hard to believe that the increasing number of big, ripped HWs like Bruno, Ruddock, Morrison, Holy (not that big, but heluva ripped), Ike etc was completely uncorrelated to steroid usage.