I speak often about the problems associated with reduced appetite in older people. Personally, I struggle to convince my appetite every day that I don't really need that extra serve or that nice home made cake that's on offer. but many, many older people say to me "I'm just not that hungry", or "I don't need as much now I'm older" and those are dangerous beliefs.
(In terms of being potentially damaging to health, possibly even more so than me succumbing to that cake!)
There is such a beast as 'anorexia of ageing' - it means eating less than the body needs, causing problematic weight loss. It happens partly as a result of age-related changes in physiology, but there are lots of other reasons and its very damaging. Thin IS NOT always GOOD once you are in your 70s and beyond. If you want to know more and get strategies to assist in avoiding the frailty that can too easily result, read Eat To Cheat Ageing - there is a whole chapter there on the appetite.
Want to learn more about how you can cheat ageing?