My mother is in her 70s.
She is a retired teacher, so she has the attitude of "always right" and "overly control" herself. Of course she lives her life beautifully, but there is time when you can not make decision for the best interest of yourself. This is not uncommon for human beings, whether young or old, we fail to make the best decision for our own good, and sometimes we tend to self-sabotage as well.
My mother is the most self-controlled person (in terms of food choice) that I have ever know. She has a long list of unhealthy/bad food. Therefore, only a narrow range of food is acceptable for her. For example, deep fried food are all bad for your health. Steam food is healthier but its bland and not appetising. My mother sometimes could even force feed herself if she is convinced enough that food is good for her, and reject "bad food" even though that she loves them so much. For years, she has a strict diet for herself: less salt, less sugar, less oil version of everything she eat. In her terms, meat are bad for health, vegetables are good, don't eat too much (70% is the golden rules), and one shouldn't eat more than an egg a day because it will lead to high cholesterol (which is NOT TRUE).
The most obvious changes that we would see when we are getting older than 40 years old, are the slow down of our daily activities, our muscles and brain functions are shrinking slowly and then rapidly in 60s to 70s. My mother is getting weaker and weaker since she has been controlling her diet wrongly, losing her weight and strength. Doctors and physiotherapy are both suggesting her to take more protein rich diets, but in her perception "meats are bad, no more than 1 egg a day" is hard wired in her brain, so much so that it has psychologically make her sick or disgust when eating more meat.
Without sufficient dietary protein and probably trace minerals/vitamin B complex from the meat source, there is no way the muscle and strength will come back. Now, she relies a lot on formulated milk and supplementary nutrients, yet, these can never be enough to support the basic metabolism. Habits and wrong perceptions are forbidding my mother to enjoy her food and reducing her day by day. I hope she can change her mind one day by reading more latest and true information, and then make a wiser and better diet decision for herself.