If you really want to gain muscle, you're going to have to make some compromises like everyone has mentioned. Namely eating obscene amounts of food when you don't want to and allowing a reasonable increase in BF.
Keep in mind a somewhat elevated BF level means increased levels of circulating IGF-1, so it can be a pretty potent anabolic environment. And as far as eating goes, you may find it necessary to supplement with protein powder in addition to ramping your fat way up. You may also want to consider dropping your carb intake significantly and doing more of a cyclic low-carb approach. The Zone is definitely not the ideal weight gain setup.