I’m often astounded by people who pipe up in the pub/bar/work that they have more/less than their calories for that day. I’m astounded because many of these people don’t really know what their caloric intake for the day should actually be. The problem is that we blindly follow that men are recommended to have 2500Kcal a day and women just 2000Kcal. WHAT?

We all know there is no “normal” person… but a generalisation of this magnitude surprises me that it has gone unnoticed. Do you honestly expect that a 55Kg man will need as much as a 110kg man? More to the point though… does he need double?

It’s honestly not that hard to work out, with a much greater accuracy than you would expect. There are a few basic ways, before going to your local laboratory to make a good estimation of your caloric requirements. Remember, if you get it wrong, by even 500Kcal/day, that’s 3500Kcal per week (over 1.5kg of fat per month!)

Step1)... The Resting Metabolic Rate (RMR)
Take your weight (in Kg) and multiply by 25 (this works for either gender). I’ll do my calculations as an example:

 75Kg x 25= 1875 KCal/24 hrs

This number is your Resting Metabolic Rate (RMR) for a 24 hour period (approximately). That is to say that if you were to be doing ABSOLUTLEY NOTHING for 24 hours, this is how much energy you would approximately burn off. Divide this by 24 to get your hourly RMR. In my case this is 78.125. I would burn 78.125 calories per hour doing nothing.

Step 2).... Time to make it more accurate
Do a quick Physical Activity Log (PAL). That is to say a rough chart of what you do in the day (you might want to do one for “training” days and “non training” days). Mine might look something like this for a training day:

00:00 – 06:30 Sleep
06:30 – 07:30 Shower, change, eat, drive to work
07:30 – 12:00 Work at desk (seated)
12:00 – 12:30 Eat Lunch
12:30 – 17:00 Work at desk
17:00 – 18:30 Change, eat, drive to gym
18:30 – 20:00 Workout
20:00 – 23:30 Drive home, eat, shower, change etc
23:30 – 24:00 Sleep

Notice how I started at 00:00 (midnight) and finished at 24:00 (midnight)? This makes it easier when you get to the next step…

Step 3)... Your Activity Diary
Arrange your data in a table. A spreadsheet makes this easier, but all you really want to know is how long you spent doing each activity. Mine might look like this:

Step 4)... Pulling it all together.

So now we know roughly how much time we spend doing each "type" of activity. There is a list of "multipliers" that can be used to determin how much caloric expenditure these activities entail. This is called the "Physical Activity Ratio" table (or PAR table). This table gives you an estimate of what a good "factor" would be for your activity.

  If you would like a copy of this table, please contact me in the forums and I'll send you a copy right away. For the moment, this is the jist of it, but in my case look like this:

See the figure at the bottom right? The 3839 number? That number is MY required caloric intake for a "training" day. See how different it is to my "recommended" intake?

This is an excercise you can do right now with a pen and paper (or a spreadsheet application if you have one on your computer). If you're a heavy weight trainer, or an athelete you should be doing this already, but if you have an interest for any reason in your health it's a good excercie.

I hope you have found this article interesting and useful. Please feel free to comment (or point out the odd typo!) in the comments or in the forums.

As always, train hard.

Matt