If writing in a notebook seems old school, there are online food journal programs you can access through your computer or smart phone.
Experts say if you're going to start a log, make sure you have it with you or can access it at all times.
Also be honest and accurate. Measure portions and read labels.
“It would also be important to maybe write down the time that you are eating so you can see if there are long hours that go by without you putting any fuel into your system,” says Sharon Zarabi, RD of Lenox Hill Hospital.