[header] How to maintain a healthy weight [title] Keep a food diary. [step] Keeping a food diary can give you a better understanding of the number of calories you're consuming each day. Estimate your portions so you can use nutritional information to determine how many calories are included in each of your meals. 
[substeps] Keep your food diary for at least a week so you can get a daily average. Take note of days that seem out of the ordinary and try to figure out why you were consuming so much more (or so much less) on that day than on others.