This "Heart attacks are the biggest killers" statement doesn't match my life experience.
My wife's boss, a good friend, collapsed suddenly of a heart attack aged 40. Otherwise only two other friends, both obese, have died from them and neither very young.
OTOH I have had a dozen or more friends, the youngest in his 20's, die of cancer and a brother, his daughter and my mother.
My experience is that the Big C is killing more and the young are not exempted.