One of my main problems with The Biggest Loser (besides the contrived part of the game existing outside of real life which is unavoidable) is that they focus so much on exercise and so little on nutrition. I get that they like to sell their cookbooks and diet plans and not give the secrets away for free on the show, but in my opinion and as others have touched on in this thread, it's at least 75% diet, if not more as a key to losing weight.
Working out is great for building muscle, strengthening your body and cardiovascular system, great for battling depression, it's awesome. However, you cannot counteract lunch and dinner at McDonalds with an hour a day in the gym. A lot of people get frustrated because they go into the gym and alter their food intake so little, and bust their asses for an hour or more a day for a month and see little results. Or see results for the first month before tailoring off.
Most people eat way too much food and that is a much bigger problem than a little less activity than our grandparents had. The combination of the two is lethal as this generation is finding out.
Eat food that spoils, eat until you are not hungry anymore. Try to get as much protein as possible.
Of course I love reading what works for others as well.