"Natural causes" sounds like a convenient excuse especially when we are talking about people below the age of 60 or so.
Statement holds true not by an immeasurable standard (forever) but by observable consequences based on behavior (in this case, consumption), given time, and application of that behavior over time. For example, this generation has the largest child sufferers of type 2 diabetes and youngest suffers of heart related problems.
Check out this dude. Looks healthy right?
Buff. In shape. Man's man. Total stud.
Dead at 26. Here's his autopsy results:
https://generationiron.com/dallas-mccarver-autopsy-released/
Steroid user for starters. Also elevated LDL cholesterol (comes only from animal products), as well as Atherosclerosis (build up arterial plaque, mostly from animal fats but also from plant fats that have been denatured through excessive heat (as with frying)).
Sort of blows away a few myths right there. I'm sort of guessing he didn't drink or smoke - but I could be wrong. Maybe EVERYTHING is caused by alcohol and tobacco products