My blood sugar is 279, how bad is that?

I have diabetes. Although that reading is not good, it's not going to kill you. You need to get to a free clinic, be tested and start taking medications. Not eating sweets is good, but it is not going to help you. Try eating high protein (boiled chicken, egg whites) salad, fruits and vegetables. Drinks lots of water and exercise every day. Get to a doctor. You have too. Long term high sugar readings will cause blindness, loss of limb, infections and kidney disease.