Amazing actor and although he was best known for the Sopranos he was much more than just a drawn out HBO series actor.
Do some research and you'll find he was nominated for other types of work and it always seemed like he brought his A game to every role.
Sad that at 51 he is gone but don't just blame the weight. Sadly, that kind of weight may have just been a symptom of a bad heart slowing down before it failed and it saddens me that no one around him got him to a heart specialist to get it checked out.
Lost a neighbor in a very similar fashion where he gained a lot of weight in a short period of time and turned out his ticker was failing and the weight gain was a symptom
I went to Colorado Springs for a business trip one time in the early 2000s, height of Soprano's popularity, and the only car they had for me to rent was a Cadillac. Guy at the rental counter told me I looked like Tony Soprano. I drove that Cadillac all over Colorado Springs like I owned the place, nailed my meetings, and flew home whistling Sinatra tunes.
RIP, the world is a bit smaller without him around.