YES! I lost 50+ inches by running each night. The more I ran, the less junk food I wanted to eat.
If you want a good place to start, try just writing down what you eat every day.
For example:
1 serving of chips
2 slices of wheat bread
3 slices of roast beed
etc.
It's a good way to see where you need to start AND a visual way to look at how much you eat (or overeat).
Also, try to just get moving. It doesn't matter what you do when you first start out as long as you move it - try swimming if your knees are bad or try walking.
I wouldn't put too much comparison into the Biggest Loser though - your goal is to lose 2-3 pounds per week, not the 5-15 pounds they lose weekly. It's not healthy to spend 6 hours in a gym. It's not realistic. The point is to make a LIFESTYLE change, not just a momentary fix.