My thoughts on guar gum is that it is an awesome addition to the Primal Blueprint diet and shouldn't be limited. use as much as you like. Use it in whatever you like.
Dietary fiber - Guide to Health | GuideToHealth.com
Guar Gum is a powerful prebiotic, meaning it provides food the the gut microbes who are responsible for your overall health. There are many other prebiotics, such as the inulin found in onions and garlic, the fructo-oligosaccharides found in bananas, asparagus, and jerusalem artichokes. Unfortunately, most people get very few prebiotics in the PB diet, so I think guar gum is an excellent choice for your homemade ice cream--eat it guilt free!