Re: Why Over Fat?
Again, if the exercise you're doing is exhausting you, then cut back on the amount or the speed you walk on the treadmill. Ideally, you should be doing 1/2 hour at a time on the treadmill---preferably with changes in elevation. If doing a 1/2 hour is wearing you out, slow your speed down to the point where you can do the time without feeling worn out. Then gradually work up to a faster speed---a little at a time.
Also, consider cutting back on the chicken and meat that you eat. I've had success losing weight by only having chicken/fish/meat twice a week, and on the days that I do have it, I only have one serving size. In addition, I rarely eat red meat on those days, instead I have fish or white-meat chicken.
Another thing to consider---you've tried many diets/herbal supplements---Just how long do you try a diet or a supplement before you give up? Sometimes you need to be patient and give something new time to work. Some say give it at least three months.
There is a CZ user, "propaul", who has put his type 2 diabetes in remission. He has a blog on CZ where he discusses how he changed his diet and made sure he got regular exercise. I suggest you take a look at it. Personally, I found it to be very helpful.