If you really want to lose weight, you should seriously think about keeping a food journal.

That’s the key message of a study published online Monday in the Journal of the Academy of Nutrition and Dietetics (which used to be the Journal of the American Dietetic Association).

The study, conducted by researchers at the Fred Hutchinson Cancer Research Center in Seattle, involved 123 overweight-to-obese, sedentary women ages 50 to 75.

Half the women followed both a diet and an exercise program, while the other half just followed a diet. Women in both groups lost an average of 10 percent of their original body weight. (This study, part of a larger one, did not directly evaluate the effect of exercise on weight loss.)

Those who kept food journals did a bit better than the rest, losing about 6 more pounds than the journal-free women.

The researchers note that the more detailed and consistent the food journaling, the better results you’re likely see. That means measuring food portions, recording every bit of food you put in your mouth, carrying your journal (or app) everywhere you go, and being mindful of preparation methods and nutrition-facts labels.

Other results:

●Women who ate many meals in restaurants lost less weight than those who ate fewer meals out; the relationship was strongest for lunch, with those who went out for lunch at least weekly losing an average of 5 pounds fewer than women who didn’t eat lunch out as often.

●Women who skipped meals lost, on average, 8 fewer pounds than those who didn’t.

I have written before that recording my food intake seems to backfire on me; my obsessive personality reacts to journaling by, well, obsessing about food. But I haven’t hit menopause yet, either; maybe one of these days I’ll have to rethink that food journal thing.

Let’s hear from you: Do you use a food journal? Is it a huge help to your weight-loss effort, or just a pain in the neck?