the maths

So today was weigh-in day and my mood is a little flat... I only lost 100 grams this week.

This got me thinking though, what does it take to lose 1kg?

I remembered reading an article that talked about weight loss in terms of numbers. Instead of being written by a celebrity trainer or health expert, this article was written by Jessica Irvine - an economics writer, and it was surprisingly helpful. (Quick fact - Jessica was also a 12wbt member.)

So I did my research and various sources weren't 100% consistent but 7500-7700 kilocalories (which are commonly just referred to as calories) equals approx 1kg. So to lose 1kg, you need to burn 7500-7700 more calories than you consume. (It is more complicated than that, but this can still be a good guide.)

Using my own approximate details (I've averaged over a week) as an example, I should be losing approximately 130 grams per day.

1200 (Daily calorie intake) - 1623 (BMR*) - 600 (Additional calories expended e.g., workout) = -1023 Cal

7600 Cal

= -0.13

*Basal Metabolic Rate (see below for more details)

One bad day won't have a drastic effect, but the more you stick to the plan, the easier it will be. If I was to add 400 calories to my daily dietary intake it would nearly halve my weight loss.

I have now started a spreadsheet (geek!) with all these numbers and hopefully instead of feeling flat next weigh-in I will know exactly why I have (or haven't) lost weight.

Who knew a little bit of maths could be so helpful?

So while we're on the topic of maths, I'll quickly touch on the maths behind Basal Metabolic Rate (BMR). But firstly what is BMR? It is the amount of energy expended daily at rest.

For anyone involved in the 12 week body transformation, your BMR has already been calculated for you and you can find it on your 'My Stats' page. For everyone else, here is one way you can determine your BMR.

Females: BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) - (4.7 x age in years)
Males: BMR = 66 + (13.7 x weight in kg) + (5 x height in cm) - (6.8 x age in years)

Once again, this maths isn't exact but it gives you a good idea.

There you go, weight loss through maths. Obviously, knowing how many calories you need to cut out doesn't exactly help you avoid the temptation of the cookie jar, but at least you'll know you can work it off by adding an extra 10 minutes to your workout.

So here's to many positive future weigh-ins!