No, not the type of journaling you did in fifth grade using your Lisa Frank unicorn-covered journal.
I was first introduced to the idea of food journaling when I started attending Weight Watchers meetings back in 2007. The concept involves writing down everything you eat. The purpose of doing this is to see--right before your eyes--what (and how much) you're actually consuming. If you've never done this, I highly recommend it. I was eating probably two to three times the food my body needed. What a wake-up call.
When I journal, I like to be able to do it quickly and have the ability to know how many calories I've eaten, so I use Livestrong.com. They have a great (free) nutrition log that allows you to enter what you've eaten and feature a massive list of foods and their calorie values including name brands and restaurants.
To take journaling one step further and to increase your chances for weight loss success, try adding meal planning to your journaling. This involves planning out your day's meals and snacks by writing it in your journal. I like to do this for a couple days at a time. The night before, I'll look at my journal (which is a pad of legal paper--nothing fancy) and get my food in order for the next day.
Okay, this may sound like a lot of work but I can genuinely tell you that the work works. It pays off. I hadn't used a food journal in months and found the scale gradually increasing so for the past two week's I've journaled nearly everything I've consumed. I have lost five pounds. I can't speak for you, but that five-pound loss is worth the five to ten minutes each day it takes me to plan out my day and write down my food.
There are so many options available in the world of food journaling. For instance, if you aren't a pen-and-paper gal, try the method I recommended above--online journaling. Here are a few of the great, free online resources, that I've tried, for food journaling: