A normal blood sugar reading should be below 100mg/dL when the individual is fasting and below 140mg/dL 2 hours after eating a meal, as stated by WebMD. In most individuals, a normal blood sugar reading will be even lower with blood sugar levels at their lowest point right before a meal. Blood sugar levels normally will not fall below 60mg/dL even with prolonged fasting.
High blood sugar levels are of highest concern as they may inhibit the body's ability to produce insulin or may result in the hardening of the arteries. High blood sugar levels can cause strokes, kidney disease, blindness, heart attacks and nerve damage.