There's no mention of baseball either. Doesn't mean they don't care about it, it just means it's not relevant, beyond the painfully obvious: a rationally selfish person should take care of their health.
Rand smoked, and her body type didn't really allow her to appear thin, but she was not obese either. Clearly she paid attention to her diet. I would write off the smoking to the Oist tendency to be skeptical of popular and government advice...because such advice is usually wrong. So it took her longer to buy into it than most.
And her husband was thin through his life. So are all the men you mentioned. I doubt that's just by coincidence. No indication that they drink to excess or smoke, either. Clearly, they value their health more than the average North American.
I know most about Peikoff's habits, because I listened to his podcast. He is very careful to maintain his weight, at all times, and has been for decades. But he does so without the "nihilistic" approach of denying himself food he craves. He just has less of it, or switches off fattening foods for a few weeks, when he notices any weight gain.
P.S. But by all means, e-mail prominent Objectivists and ask. You'll probably get an answer from some of them. Or show up to an even they're speaking at, and ask. I'm sure you'll get the same answer back: health is obviously a value, and we should take care of our bodies.