It doesn't get any simpler than this: eat less crap and eat more food.
This simple statement can make a tremendous impact on your bodyweight, your body composition and your longevity. If it's so easy then why doesn't everyone do it? Because it's simple, but it's not easy!
Making big changes are hard to do so why not make a series of small changes and see what happens. For example, why not start your day with a high quality protein shake? The shake will break your "fast" with a boost of protein and curb your hunger pangs (helping you get away from bagels and donuts). Next, how about taking another small step by removing processed sugar? Don't add it to coffee and don't consume it in your fluids... it's harder than it sounds, but the payoff will be huge. Now about increasing your consumption of water? You can lose almost ten pounds a year if you take soft drinks out of your diet - not to mention that you'll take a whole host of chemicals and sweeteners out of your diet.
Think about it - a small change, implemented over time, can have a tremendous impact on your life!