I'm overweight, and have been most of my life. I'm 31, 5'11, 285 pounds, and have an extremely hard time sticking to a diet.

Last year, I was doing well with exercise, using a rowing machine for upper body, and elliptical for lower body. I lost 20 pounds in two months, but due to life events, stopped going to the gym, but maintained with walking, and running as convenient.

Over the winter, I stopped the walks & runs, and gained back 10 pounds, bringing me to my current weight. I'm now signing up with a gym again, and believe I can commit to it three times a week for about an hour and a half. Is there a more efficient workout other than elliptical for lower body & rowing machine for upper body for fat burning? I want to stay away from the high impact treadmill.

I'm also planning on increasing my intake of water, cutting out the soda, but not necessarily changing what I eat much, as that never seems to work for me.

Any other suggestions to help burn fat as quickly & efficiently as possible?

Optional Information:
Person's Gender: Male
Person's Age: 31

Already Tried:
Stated in question.