What's the first thing I think anyone who wants to lose weight should do? Keep a food diary. All you have to do is write down what, when, and approximately how much you eat and drink every day in a notebook. No need to try and figure out calories at this stage. It is simply an exercise designed to make you more aware of your current eating habits so you can identify what changes need to be made to lose weight. This food consciousness also helps you to plan healthy meals and snacks.