I gained a ton of weight when I got a desk job and a car and a wife (I blame the wife) but the doctor said it wasn't the weight ... for some reason the nerves in my heart just decided not to work properly. I don't think a few extra pounds (or even half a human's body weight, in my case) are necessarily the cause of the OP's issue.
Vegas (Nevada generally) is pretty dry. Dehydration seems more likely, or maybe something else ... if trouble persists, see a doctor.
I know more than a few riders with sizeable aero-bellies who can kick out high speeds over distance ... their legs, lungs, and hearts are fine, and they enjoy food and beverages as well. Not a bad life. My lungs and heart are not fine, so the weight is an issue, but for some folks ... go for the gusto. Never saw an epitaph saying., "I wish I had enjoyed desert less."