Some advice on losing weight and losing it fast:
1.) Cardio in the morning before breakfast. It is said you can burn 3 times more fat at that time. Glycogen is low when you wake up because you've been asleep for approx. 6 to 8 hours. If you were to start doing cardio right after you got up (no breakfast), you'll start burning fat instead of glycogen because there isn't any stored in your system. Drink a glass of water before you start. Have breakfast after.
2.) Eat breakfast. I love plain oatmeal in the morning. The water soluble fibre in oatmeal is what makes it take longer to digest giving you that I'm full feeling for a longer time. Plus, it kickstarts your metabolism. Eat wise at this time as this will dictate the day.
3.) Eat more meals and less portions throughout the day. Forget about 3 square meals. That just slows down your metabolism which causes you to eat junk in between meals. Eat about 5 to 6 meals a day and keep the portions small. Limit your carbs at dinner and try not to have any after. My go to late night meal is high fiber cereal but I rarely eat after dinner. The pounds melted off of me when I started implementing this routine.
4.) Get plenty of rest. So much happens in terms of internal body chemistry when sleeping. A solid 8 hour sleep is best. I wish I followed this one more seriously but with the baseball playoffs on and a new hockey season, it's kind of tough.
5.) Exercise. Not just cardio but hit the weight room. If done with a good intensity, it offers a great workout. Lift and then jog. You will be melting off the weight.
I remember in 1994, I was overweight and did something about it. I joined a gym and for that first year, I was there 3 to 4 times a week jogging for 30 minutes. No weights, just jogging. I didn't change my diet either. The results after that first year was me maintaining my original weight (208 pounds). I didn't put on weight but I didn't lose either. There was so much I didn't know about weight loss and what I needed to do. The internet was just getting off the ground at that time.
Cut to over 10 years later. I'm now down to 190 pounds and I'm hoping to get a bit heavier with muscle weight. I've lost a lot of belly fat as well. I was pushing a 38 on my waist size. I tried on an old pair of Eddie Bauer khaki's (size 34) the other day and it fit me perfectly. I'm on the internet a lot reading about weight loss techniques (for motivation) and while some sites disagree with this diet or that diet, the tips I listed above are about the only thing that's agreed on.
Good luck on your upcoming surgery.