http://www.laurassoapbox.net/2014/01/we-need-to-stop-calling-it-non.html and else where I heard much, enough already.
Non-compliance is a term that there is much whining about, when it simply means that the subject is not following the plan, and it must be the subjects fault as our plan is good and sound, well perhaps not, but it is our plan. No one may be able to follow it, but if you could, the problem would go away. With diet, the typical plan is three meals per day, possibly snacks, and likely specifying or excluding some foods or food groups.
As I have struggled with weight issues my entire life, I have watched what and how people eat, and I can tell you that most people do not comply with what the health professionals say we should be eating. Many of them also do not comply with there own advise.
I see people not following our recommendations, in my engineering work, we say they are non-compliant, aka not following directions. What can I do? We recommended what was good and right and true, and they are not following it. It is their problem, and may become the owners. Get over it.
Whether they could follow the plan or not is irrelevant. Now perhaps the plan did not address the real problem. Diet is driven by convince, cultural, historic, physiological, psychological, philosophic, spiritual, thinking, feeling, behaviors, habits, emotional, environmental and well as just change issues. Start with philosophical, for that can overcome much shit.
Are you (or the subject) willing to delve into all these areas of your life? Are you willing to change, and to study change, or just whine in the precontemplation and contemplation stages? Are you willing to tear your personal philosophy apart and clean it up? Recovery requires compliance, if you are not willing to comply, you are non-compliant. Get over it or not. Get on with life or not. It is your choice. It is the subjects choice. You may be deeply troubled by the actions of loved ones, but you cannot change them much, they need to change themselves. Kiss them goodby, for they are mortals, and will die. We can only change ourselves.