When it comes to weight loss, one of the best predictors of success, believe it or not, is keeping a food diary.

A new study gives further evidence about the effectiveness of this very simple weight-loss tool.

Scientists at four clinical research centres in the United States recruited more than 1,600 men and women over the age of 25 who were overweight or obese with high blood pressure and elevated blood cholesterol.

As part of the study, people attended group meetings for nutrition and behaviour change, were told to consume 500 fewer calories per day, eat lots of fruits and vegetables, exercise and keep a daily record of their food and physical activity.

Interestingly, the people who kept the food records lost about twice as much weight as the people who did not.

A number of other studies have shown the effectiveness of keeping a food diary.

Dietitian Anne Fletcher, author of best-selling book Thin For Life: 10 Keys To Success From People Who Have Lost Weight And Kept It Off, interviewed more than 200 people who had lost a substantial amount of weight and kept it off for more than three years.

In her book, she tells their success stories and tells how they mastered their weight.

She writes that quite a few said keeping a food diary is one of the most important things they do to keep their weight down.

So why does this work?

It helps you become aware of your eating behaviours and it helps you track your progress. It's a good way to see exactly what you eat as well as some of your behaviour patterns.

These patterns are invaluable as you start to set goals for change.

Once you have a realistic picture of what you are eating, you can begin to identify some areas to work on.

It also helps make you aware of mindless eating -- that nibble here, nibble there, that can contribute so many "unaware" calories.

The diary can help you focus on your goals and also help you think twice before you take a second helping or reach for that 4 p.m. danish.

NUISANCE

In my practice, I always suggest that my clients keep a journal. Even though many find it a nuisance or just don't want to do it, they are always surprised and pleased to find that it really helps them.

So, if you are struggling with your weight or trying to master your cholesterol or blood pressure, give food journalling a try.

There are lots of tools that can help.

Some people carry a little notebook or daytimer with them, some set it up on their computer or BlackBerry.

There are even some computer programs available that have journals already set up in them.

The most important part of the exercise is to do it consistently, honestly and in a non-judgmental so you will gain the real benefit.