Keeping a food journal — a detailed account of what you eat and drink and the calories it packs — is a powerful tool in helping people lose weight, U.S. researchers have concluded.

A study involving 1,685 middle-aged men and women over six months found those who kept such a journal just about every day lost about twice as much weight as those who did not.

The findings reinforced earlier research that endorsed the value of food journals in helping people lose weight. Health companies including Weight Watchers International Inc use food journals in their weight-loss programs.

For people who are working on weight loss, writing down everything you eat is a pretty powerful technique. It helps people to see where the extra calories are coming from, and then develop more specific plans to deal with those situations.

A study published in the American Journal of Preventive Medicine reinforces what I already have seen over the last decade in my clinic. Writing down what you’re eating helps keep dieters accountable for what they are eating.

The study involved people from four U.S. cities: Portland, Oregon; Baltimore, Maryland; Durham, North Carolina; and Baton Rouge, Louisiana. Their average weight loss was about 13 pounds. But those keeping food diaries six or seven days a week lost about 18 pounds, compared to 9 pounds for those not regularly keeping a food diary.

The average age of people in the study was 55.

They were asked to eat less fat, more vegetables, fruit and whole grains, exercise 180 minutes a week- mostly by walking, attend group meetings, and keep a detailed food diary. Current exercise recommendations are at 150 minutes per week, but obviously, if you can do more, that’s a bonus for your muscles and bones.

Keeping a food journal doesn’t have to be a formal thing. Just the act of scribbling down what you eat on a Post-It note or scrap paper or sending yourself e-mails or texts tallying each meal will suffice.

When you work with me to attain your health goals, I provide a structured way to keep your food journal so that we can review it together and I can make recommendations on changes needed in order to reach your health and weight goals.

Clinically, I’ve found food journals to be one of the most powerful tools I can use to bring about the changes needed for patients to get to the level of health and wellness they’ve been seeking.