How To Calculate How Fast You Can (really) Lose Weight

Fat is what you want to lose. Not water, not muscle, and not bone mass.

Despite what you read in supermarket magazines, and despite decades of very sophisticated attempts by medical researchers to find one, there simply isn't any known way for your body to "flush out fat" without burning it, or to "burn it off"  without first needing the energy to keep you alive and move you around. (We can dream about finding some such method, but so far liposuction is the only thing that's even close.)

A pound of fat stores 3500 Calories of energy. You can lose that pound only by using-up 3500 Calories more than you eat. For example, if you eat food every day that has only 2000 Calories in it and at the same time use up 2500 Calories living, working, playing, and "running-around" -- and you can do this every day for seven days, you'll lose one pound of fat.

How can you do this?

First, you need a food & nutrition technique that lets you really control the number of Calories you eat -- nothing else works if you can't do that. The method has to eliminate hunger as well as Calories, because no one can stay on a diet that keeps them constantly fighting hunger for long enough to lose enough weight. (Giving you such a method is what this website is all about.)

Second, you need to know how many Calories your body will burn if you don't exercise, and how many more Calories you can burn if you do exercise. 

From this you can calculate about how fast you'll really be able to burn fat.

Finding out how many Calories you can burn off in an average day and how much control of this you really have is a three step process:

Here's an example.

1. Calories Used to Just Stay Alive

If you are female, age 30, weigh 200 pounds, and spend the whole day lying down quietly in a warm room, your body will burn about 1850 Calories. (You have no practical control over this calorie-burn rate.)

This is called your Resting Energy Expenditure (REE). It is the minimum amount of energy your body needs in a day.

Note: To recalculate the above example for your own gender, age, & weight, use the method covered previously (How Many Calories Should You Eat Daily in Order to Lose Weight?).

2. Calories Used to Move Around Doing Normal Things

In addition to this REE, add the Calories you'll burn at your normal activity level.

If the same 30 year-old, 200-lb female has an activity level at a basic "office work" level  (very light),  she will use about 550 additional Calories per day moving around and doing things.

This is called your Activity Energy Expenditure (AEE). It is the amount of energy your body needs to move you around in your normal activities for a day.

This means that her normal daily activities will burn a total of about 2400 Calories daily.

3. Calories Used for Exercise 

How many additional Calories can you burn by exercising?  (Preview: It's significant, but not earth-shattering.)

It is very unlikely that a normal person can regularly spend more than about one hour per day exercising. (You have a job, probably a family, and certainly quite a few other demands on your time, energy, and commitment.)

(We've heard that there is a "one-in-a-thousand" person who can regularly do two, three, even four hours of voluntary additional exercise daily; but we've never actually met that person and aren't sure he/she really exists.)

If our 200-lb female simply walks briskly outside for one hour every day, She will burn an extra 435-545 Calories. (As her weight drops from 200 pounds, she will burn less because she won't have as much weight to carry.)

Use the Calories Burned table below to calculate about how much you would lose at your weight by walking or doing other activities.

This means that our 200-lb, 30 year-old, female office worker can reasonably expect to be able to use up a total of about 2900 Calories every day.

How much weight she will lose, and how fast, will depend on how successful she is at controlling her Calories from food.

For example, if she has an effective technique for controlling food, she will probably be able to eat about 1500 Calories per day indefinitely (meaning with no hunger or food cravings that erode will-power.)

This means she can reasonably create a 1400 Calorie per day deficit; which works out to 2.8 pounds of fat lost per week. (1400 x 7 ÷ 3500) = 2.8)

This is the reasonable rate of weight loss.

Calories Burned in Various Activities:

These figures apply to people weighing 150 lbs (70 kg).
For each 15 lb over (or under) this, add (or subtract) 10%

Note that by the above table, a 150-lb person walking at a comfortable speed for one hour burns about 360 Calories. Therefore, if you’re eating only 1500 Calories a day, this will burn one quarter of your total daily energy intake—which “ain’t bad” for an easy one-hour walk. 

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