I came here in May and have a similar story. Actually, I was quite over weight, by over 100 lbs. I was a very active guy, however, and no high blood pressure. I am also 6'3", so my weight will be higher than your average Peruvian all the time. Before leaving the US, I had one last physical with my doctor and he said everything was great, and actually getting better in terms of cholesterol and things. When I got to Lima and had a physical for work my first day in the country, they told me the same, except my BP was high. I told them sorry, just nervous being in the country for the first time, not knowing anybody, and having trouble with the language. They said ok, we'll check you again in a few days. It was still sort of high, but I was still really nervous. They said I have hypertension, and started telling me it is my American habits that cause my BP to be so high. And it would be very dangerous to move to Huaraz and work at 14,000 ft. I just was like whatever, prescribe me some pills, and we'll see how it is in a few days. I moved to Huaraz, and my BP dropped over 40 pts.
Now, fast-forward to December. I am about 60 lbs lighter, speaking really good spanish, and enjoying life. People that saw me when I first arrived, namely one Peruvian girl I met dancing, are afraid for my life. She saw me leaving a disco in Huaraz, and offered me the burger she was eating. She is quite the flaquita, so I just had to laugh. Even at work, no one really ever called me fat (actually, they called me chiquito for a while). Now they want me to get on the scale every week just to see how much I have lost.
Another interesting story. My boss saw the truck I drive in the US one day (a black GMC Sierra), and the camera I own (a Canon DSLR), and knew that I didn't have a girl friend, so he asked me if my penis was small. If I'm lying, I'm dying. Then, two weeks ago, a supervisor here was putting together a chocolatada, and asking everyone to bring in a paneton. I said I would rather bring in home-made cookies, if that is alright. He said, "Oh, are you gay?" So I think it is just their style to be blunt, even if it is none of their business or it might hurt someone.
"A man's character may be learned from the adjectives which he habitually uses in conversation." -Mark Twain