If you are intending to go for avoiding weight gain, a food diary is the first step to help you. Most of us are not really ready for the changed routine, but by keeping a food diary, you can take account of the food you intake. For avoiding weight gain process, a food diary is an immense aid. There is a variety of fat food. Not all of them are bad for us; some of them are not only good for us, but also will in fact help us for avoiding weight gain and live a healthier life. So you can keep a note of which ones affecting you in what way in your food diary and that would eventually help you for avoiding weight gain.