I have been running into a certain type of person way too often lately. The know-it-all. (More often than not, it is a Mr. Know-It-All). Being a know-it-all is awesome IF you do in fact know what you're talking about. I find with fitness and nutrition, the if just isn't there.
Here is a little tip for you. If you are overweight and out of shape, don't tell the person who is trying to help "Oh I know what I'm doing, I've working out for a long time." Or the famous "I know everything I need to know about this stuff." Really? Because I have a degree in this field, I have been working out for over 20 years, I study every day, and what I have learned is that I have a lot more to learn.
To steal from the sports world, be coachable. You are probably awesome at your job and a very intelligent person as well, but that doesn't mean you can't learn something. Success leaves clues. It's time to get your magnifying glass out.
A guy I know, Big Will from Mobile, when he was a drill sergeant would tell his soldiers, "All your way did was get you overweight and out of shape. Your way don't work. I've been doing this for a long time. It's about time you started listening to someone else."
Don't do this for the person trying to help you, do it for yourself. All you are doing is insulting the person helping you and hurting your chances of succeeding. The people that progress the fastest are the ones who sacrifice their ego for the sake of getting better.
Do you know it all?