Is it possible to be genetically predisposed to being fat?!

I have always been overweight in my life. In the past year and 3 months, I have been rigorously dieting and hitting the gym six out of 7 days. I haven't lost a single lb, in fact I've gained 2 lbs in that time. I have seen 4 qualified dietitians and hired 5 personal trainers during that time, all kept repeating the same quote quite eerily "it is a slow process; don't expect to lose weight overnight". I haven't once cheated while I was on the diet and I exercised on a consistent basis, pushing myself with heavier weights every 2 weeks at the discretion of my personal trainer. I was 266 lbs a year and a 3 months ago, and now I'm 268 standing at 6'0 ft tall. Am I just genetically predisposed to being fat? I'm a math instructor at a community college, so my job does not require me to be physically fit. I don't think I'll ever try going through that torture again, seeing as it did not even come close to yielding the desirable results.