Certain habits and behaviors predict success in the weight-loss arena. One of them is keeping a food diary. A new study from Kaiser Permanente shows that people who keep a food diary actually lose twice -- that's twice! -- as much weight as people who don't.

A successful food diary is about more than just writing down what you eat. I like to have people record not only what they eat, but how they feel. What's your energy like? How are you sleeping? Getting tired in the middle of the afternoon? All this helps make connections between the foods you eat and how you feel, so you can fine tune your diet for maximum oomph and energy.

One of the reasons for writing down what you eat is so you can estimate your calories. That means you've got to measure stuff -- at least for a while -- and then use the Internet or a calorie book to approximate how many calories you're taking in. This calorie-estimating was an important part of the success of the Kaiser program. (Note: It's not nearly as hard as you might think since most of us eat the same dozen foods over and over again.)

And forget all those online calorie formulas -- they're way too high. A good rule of thumb is this: Take your target weight and multiply by 10. That's a good number of calories to aim for while you're losing weight.