Why does my BMI say I am obese when I workout everyday?

I workout during the week before work at least 20 including weight lifting. On the weekend I workout between 60 to 90 minutes a day. Which included kickboxing walking and weightlifting some form though out the week. I eat between 1200 and 1600 calories a day and 8 gles of water. I am solid, as in my arms and my legs and back shows all my muscles everywhere except for my lower stomach (around my hips). Also I am hourgl body shape too. So, why does my BMI say I am obese.