"thanks :) I might try this, but how does this help? I just need to lose like 4 or 6 pounds... "
Why keep a diary? Being more self-aware helps tip you off to behaviors and calories that contribute to weight gain, and helps you break bad habits. By writing something down you become accountable for it, and that can be incredibly motivating. In fact, food diaries are so important, we consider them essential. Get started on yours, and you’ll see why in just a day or two. Download blank food diary page (pdf).
Start by writing down everything you eat and drink today. A few ground rules:
Keep it handy. Take your food diary with you everywhere, so it’s always at the ready whenever an eating opportunity presents itself (say, that sliver of cake at a surprise office birthday celebration). For convenience, you can also use a small notepad to write down what you eat, then enter the list in your diary later.
Write it right after you bite it. That way, you won’t forget anything, especially quantities. Don’t forget condiments, like that pat of butter on your green beans. Be sure to include those “incidental” nibbles that are notoriously easy to overlook—like that last quarter of a grilled-cheese sandwich you polished off when your child left it on her plate, or that mini candy bar from the jar on your co-worker’s desk.
Be specific. Record the type and amount of food in as much detail as possible, especially portion sizes; list “10 crackers,” rather than “a handful,” or “2 cups popcorn” rather than “small bowl.”
Record calories. Look up the calorie value of the foods and drinks you’ve had today, making sure to adjust for the portion size. For example, if that portion of ham in your sandwich at lunch was larger than the 1-ounce-slice serving listed, make sure to adjust the calories accordingly. If you can’t find a food you’ve eaten on the list, check food labels or other standard calorie-counting guides.
It’s better to add up the calories as you go, rather than waiting until later; that way you’ll have a running tally of what you’ve eaten. But if you don’t have time to do the math each time, don’t sweat it. Do the best you can, and add up the numbers at the end of the day.