Brian Shaw is extremely obese. There are no two ways about it. Even with the fact that he is extremely tall, still 450 lbs of weight puts a lot of stress on the heart as that much weight requires pumping a lot of blood to provide Oxygenated blood to all extremities. The sooner he comes to the realization, he will have a chance of living a long, healthy life, but if he continues being 450+ lbs, it is just logical and science that he is going to have a lot of health problems.
I see you are also a Strongman enthusiast since you have you have Felix in your avatar. There were really smart strongmen who realized and made the adjustments. I remember looking at Strongman legend Zydrunas Savisckus and he looked completely unrecognizable.
Left is how he looked like when he was competing in the strongest man competitions and right is how he looks like now after he retied.
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