What you eat is, in my experience, more important than how much you eat. If you eat better food, your appetite will regulate itself.
Europeans eat on a daily basis what many Americans consider luxuries and in many cases are considered to be "bad", but Europeans don't have the health problems, including the obesity problems, that are endemic in America.
A lot of it can be tied to excess processing of food, which includes processing to give a longer shelf life, processing to modify it's taste, usually through the addition of sugar and/or salt and even processing the food in a way that will cause it to make you hungry more frequently, hence causing you to buy more of that food.
I plan (and hope to follow through) on being in my 70s and still being out hunting. Old Hunter and Mt-Mike, guys like you give me something to look forward to, so thank you.