What is the meaning of [Gluttony kills more than the sword]

More people die from overeating than are slain in battle. this is a very old
proverb, dating back to the times when gluttony was more common than it is
today, and it was no rare thing for people to die of a surfeit of this or that
(King Henry I is reported to have died of surfeit of lampreys). Of course, in
many cases the real cause may have been ptomaine poisoning, arising from the
quality rather than quantity of food eaten, but for all that, this is not a
bad motto for those who want to lose weight.