I'm definitely a few days late in posting this. I'm not even going to quote a single passage out of this fantastic piece from Federico Viticci. Just do yourself a favour and read the whole thing. It's excellent and worth your time.
Although my circumstances pale by comparison, the iPhone, its apps, and accessories are a major factor in my own health transformation over the past several years. Since I got my first iPhone—the iPhone 3GS—I've lost more than 40 pounds and am in much better shape than ever before in my life. The convenience of being able to track all my food, sleep, and exercise on a device that I always have with me was a huge leap forward for me, and quite frankly, removed excuses. There's no reason why you can't take 30 seconds to record your meal or your workout.