I have lost 40 lbs so far. 1/3 of the way there

Back in July, I decided to get myself checked at the doctor after my brother was hospitalized with complications due to diabetes and congestive heart failure. I was diagnosed in the pre-diabetes stage, so that was a mixed blessing. I know that I didn't want to get diabetes and so I decided to make a lifestyle change. I began by changing my eating habits, doing portion control and eating more vegetables. My gym owner said I needed to watch my calorie intake. I started walking 15 minutes a day and build up from there. Thanks to MFP, making lifestyle changes, etc, I am power walking 2-3 miles a day, I have begun high intensity interval training, and have a lot more energy. I started at 336 pounds, and as of this writing, I am 296 pounds after 10 weeks. My goal is to reach 215 pounds.