Strategy - Calculating Calories

Ok, so I've got a clear, objective, measurable goal - weight of 167 by December 13th.

Now I need a strategy of how I plan to acheive this goal.

It's clear this goal is acheivable, it will be based (in the simplest way), but what food I eat and how much exercise I get between now and the 13th.

So then the question becomes, what foods should I be eating, how much exercise should I be getting?

I like to take a scientific approach to this, I'd like to share with you the methodology that I'm using...

First off, let's clarify what it means to 'lose weight'...

1) We need to understand that our total body weight can fluctuate from 2-5 lbs in a day, based on time of day, the gross weight of food we've eaten, loss of fluids due to sweat from exercise, trips to the bathroom, retention of fluids related to consumption of salt, etc.
2) When we say we want to lose weight, generally we mean we want to lose FAT.
3) 1lb of Fat is equal to 3500 calories

So now we can start use some math to drive out what we're trying to accomplish here.

If my current weight is 182, and my desired weight is 167, I need to lose 15 lbs of fat.

15lbs of fat = (15 x 3,500) = 52,500 calories.

I want to acheive this goal in 54 days, so each day I need to 'lose' about 1,000 calories a day.

To be honest, this is a pretty aggresive goal, about 500 calories a day is perhaps more realistic, but I really want to make this a priority, so I'm going to shoot for this, I'm confident that a combination of healthy eating and exercise will get me there, and it's not so fast that it's dangerous or anything.

Ok, so we've established that I need to 'lose' 1,000 calories a day, how can I tell if I'm doing this - we know that the scale can fluctuate based on the points I mentioned earlier, so on a daily basis the scale won't necessarily be reliable. Instead I need to track the inputs and outputs...

Inputs - the food I eat
Outputs - how many calories I burn

Tracking the food I eat
Quite a while back, I joined a great, free, website called Spark People (www.sparkpeople.com) it offers some good tools to track nutrition, most common foods are already in their database and include the core nutritional info (calories, fat, protein, etc).
So I'll be using this tool to record all of the food that I eat, so I'll have a pretty accurate understanding of how many calories I eat each day.

How many calories I burn
This is a combination of 2 factors:

Basal Metabolic Rate (BMR)
The first number is to understand, if I did nothing, if I layed in bed all day, how many calories would be burned by the body on it's own - keeping my blood pumping, breathing, digestion, etc. This is typically referred to as Basal Metabolic Rate or BMR.

There are a number of BMR calculators available on the web, google it, and you'll find a bunch, I'll try 3 different ones, in case they use different algorithms and use the average.

1) Discovery Health - http://health.discovery.com/tools/calculators/basal/basal.html = 1848
2) BMI Calculator - http://www.bmi-calculator.net/bmr-calculator/= 1851
3) Glow.ca - http://www.glow.ca/Glow/GlowWebsite.nsf/GlowInfo/bmr = 1843

So, as we can see, they're all pretty close, and given that I'm talking about losing 1,000 calories a day, 5 or 10 either way is irrelevant, so let's just round to 1850/day

Exercise
Obviously when you move around, you burn calories. Spark People, and many other sites offer tools which provide estimates of calories burned performing various types of exercise. So I'll plan to use these tools in order to help.

So essentially my daily game plan will be this:

Calories Consumed - BMR - Exercise = -1,000

or another way to put it:

Calories Available to Eat = (BMR (1,850) + Exercise) - 1,000

As I mentioned in my note earlier, it is a pretty aggresive strategy. If I were to get no exercise whatsoever, I could only consume 850 calories a day, a pretty meagre diet for sure. So the key here will be for me to get approx. 500-1000 calories a day in exercise so that I can eat a more satisfying diet in the 1,350-1,850 range.

I'll post more later on what I've learned about food choices, and how I can build a healthy, satisfying diet with a budget of 1,350 calories. Now I'm off to eat an apple...

What are your thoughts? What have I missed here? Any other web sites or tools I should consider?