You could point out that half of your genes come from her and your way of eating may work better for her because of that.
I keep wanting to say, "Kalli! You need to do/say 'this and that' to convince your mom!"
I understand the frustration
Have you tried pleading with her to give it a try for one month and that if it doesn't help she can go back to her other way of eating?
I hate that she's having all this trouble and you're having to sit by feeling like you have the answers to her problems and no one wants to hear the answers, and to top it all off she's being given out-dated dietary advice based on bad science.