That's a good question, it's a question that I am trying to find the answer to, I am currently "on the Paleo Diet" right now (2016-02-07), I have been eating the Paleo way since 2015-12-25, early days, but all is going as planned so far, yes I started doing it on Christmas Day to avoid a new years resolution lol. I always fail at New Years resolutions, so I avoided making one, but it was time to make some changes and I wanted to give myself the best chance to succeed.
Although it may be anecdotal evidence and not scientific, there are some basic facts that really can't be disputed, being overweight is counter productive to ones health, eating healthy foods can only be good for you, cutting Sugar and processed foods out of your diet is beneficial for your health, the evidence is mounting that eating a whole food diet is the way to go, for a better health outcome. If you have a Chronic Illness of any kind, why not be the healthiest you can be so you don't suffer from issues that can be avoided, it's only logical, isn't it?
My mood has changed to a more positive one, rather than constant negative thoughts, I guess achieving something and being in control of your diet and getting out there and exercising no doubt helps with being more positive about things.
More to come, it's late and I need to sleep lol...