Hi Sue and Big Jim
I think it all comes down in the end to how badly you want it. A diet - any diet - will do so much for you, but if you are determined to have a turning point and change your life and your health for the better, you can do it!
Whatever system you adopt, you need to be doing something that you believe in. I like Cohen's because I understand how it works, I find plenty of independent research to back up the general ideas, it's easy for me to do, being just ordinary food I would have no trouble finding anyway. One thing is for sure, as Cate says, it really does change the way you think about food, and I can also say once getting over the first few weeks, I FEEL BETTER THAN EVER on the diet. I have lost the weight quicker and with less stress than any other way I've tried to do it over the years (there have been plenty!!!).
It also never leaves your mind. Whatever happens in life, you always know what to do to get back on track and stay within reach of your goals.
In the end, if you want it badly enough, read and understand all about it and just go for it. There are a lot of people on here who've done really well, and on other forums, and it really is best to just go with the plan and do EXACTLY what they say.