Amanda Ursell explains why just making a note of everything you eat can help you lose weight

Most of us don’t really make the connection between how we feel and what and how much we eat until we take the time to keep a food diary. A food diary is nothing more than a place where you jot down the food and drinks you consume throughout the day, with a little reminder of where you were when you ate them and how you felt at the time. A small notebook that you can put in your pocket or handbag is fine.

You may find it a bit of a nuisance to begin with, but keep a record as you go through the day rather than doing it from memory in the evening. Leaving it will inevitably lead to inaccuracies, however good your memory. Take a week or so of writing things down before making changes to your normal habits to get a realistic overview of your normal eating habits.

Here are 10 good reasons to keep a food diary

1. Nearly all of us underestimate what we actually eat

We don’t do this deliberately, but if you ask someone to recall what they ate yesterday, they will inevitably leave one or two things off the list. Studies in which people have stayed in a room for 24 hours while being constantly videoed show that on exiting the room, when asked to tell the researchers what they ate, still under-reported by about 300-400 calories, even though they knew they had been constantly observed. This "food amnesia" is just a fact of life. If you jot down what you eat as you go through the day, you will be able to get a clear understanding of your usual daily intake and use this to make small but significant changes to your future routine.

2. We also understimate what we drink

You will also be making a note of everything you drink. It is even easier to forget drinks when recalling your daily consumption than food, yet cups of tea and coffee add milk and sometimes sugar to your daily calorie total, and juices, smoothies and fizzy drinks do the same, yet "liquid calories" are something most of us just ignore.

3. Alcohol can contribute a surprising amount to your daily total

Include alcohol in your inventory, including the strength of the alcohol and the size of the glass because alcohol calories also count and can contribute a surprising amount to your daily total. Once you have recorded your total, work out the daily units within your consumption. Remember that a unit of alcohol is a 125ml glass of 9% alcohol by volume wine, a single pub-sized shot of spirits, and half a pint of standard strength beer or lager. Include any mixers you had with your drinks, such as tonic water and orange juice. Doing this will allow you to plan changes in your drinking habits.

4. It makes you think about serving size

When jotting down what you eat and drink, also estimate the size of your serving. It is really easy to plough your way through large servings and "seconds" without thinking. If you are having something like breakfast cereal, weigh the amount you usually serve and compare it with the standard serving suggested on the pack. Do the same with rice and pasta so that you begin to get an idea of how your servings compare with "normal" servings so that you can adjust the amount in the future. This is a learning tool, not something you will need to do for ever.