I hope not for your sake but a BMI > 30 (like mine) is considered obese. If you're young with a good B/P and no other obvious medical symptomatology they may let you slide. Like DTB said, the doctor holds all the cards.
Not at Prime. You'll need to bring your doctor's documentation of your health concerning this, and you may need to buy another machine. The FMCSA requires that your machine is able to download data showing your use of it to maintain your medical certificate.