A Weighty Issue

So I've registered for the Melbourne half marathon, more as an incentive to get back into running than for anything else. I'm pretty slow but have run three marathons (Thailand Temple Run, Bangkok, Edinburgh) and a few half marathons (Sydney, Melbourne, Singapore), though that was some time ago. I've got a couple of months to train so we'll have to see how it goes.

I'm fairly heavy now, at 82kg, and want to lose about 8kg for the run. Losing weight is a simple matter of mathematics. If you USE more calories (a unit of energy) than you CONSUME, you will lose weight, and you can even calculate how much.

USE: Even if you do absolutely nothing all day, you will use about 1 kcal per hour per kilogram of your weight. For me that's about 80 kcal per hour, or about 2000 kcal per day. For running or cycling I use an additional 700 kcal per hour, and for walking it is about 300 kcal. So I'll use about 2000-3500 kcal, depending on my level of activity, which I hope to keep at 3000 or more.

CONSUME: Calories are consumed either through fats (9 kcal per gram), carbohydrate (4 kcal per gram) or protein (4 kcal per gram). There are lots of websites that allow you to calculate your calorie intake. Cereal for breakfast, a nice focaccia for lunch and spag bol in the evening, with no snacking and sticking mainly to drinking water and tea, and I'm at a minimum of about 1650.

Which gives me 3000 - 1650 = 1350 as my biggest deficit. As there are 9 calories in 1 gram of fat, I should be losing 0.15kg a day, which is about 1kg a week, or 8kg in eight weeks. If I can keep it up, that is.