Purpose

The purpose of this post is to spur discussion on the amount of calories necessary to maintain one's weight. I've seen a number of people doubt that they are taking in enough on these forums. In addition, I've seen quite a few people wonder when they will lose their 'gut', having reached or surpassed their target weight. When in doubt, I like to review the available calculation options. The anecdotal experience of the people on this forum is great, and I think everyone could benefit from having it at this point.

Please note that "*" is multiplication and "/" is division in the below formulas.

Myself as Test Case

I'm going to throw down some statistics about myself and demonstrate how each formula results in a different caloric rating.

To start off with, I'm 5'11", male, 23 years old, 172 lbs, and have 17% bodyfat, which puts me at 143 lbs of lean tissue. I work out moderately (in the grand scheme of things, after coming back from the gym I sit at my computer all day).

All of the below formulas are for weight maintenance, not loss. Many good articles extend the issue on how to manipulate the fundamental value derived here for your goals of cutting or bulking.

Before we get started, I would like to highlight the phrase "TDEE", which means Total Daily Energy Expenditure.

Weight in lbs w/ a multiplier

Take your weight in lbs, multiply it by a number that almost heuristically assesses your workout levels, and the result is how much
you eat.

Doesn't take into account your lean body mass, doesn't take into account your gender (the purpose of gender is to assume average lean body mass in most caloric formulas).


My results
TDEE = 16 * 172
TDEE = 2580


The Harris-Benedict Formula for Basal Metabolic Rate

The basal metabolic rate factors in your height, gender and age which are all factors in determining your TDEE. It is supposed to be pretty
accurate for people who are not too overweight or underweight. As you will see below, I fall into neither category, having 17% bodyfat, and being placed as normal on the American BMI chart.

Before we do the calculation, we must figure out the activity multiplier. (Wording borrowed from fitren.com - see bibliography).


Sedentary = 1.2 (little or no exercise, desk job)
Lightly active = 1.375 (light exercise/sports 1-3 days/wk)
Mod. active = 1.55 (moderate exercise/sports 3-5 days/wk)
Very active = 1.725 (hard exercise/sports 6-7 days/wk)
Extr. active = 1.9 (hard daily exercise/sports & physical
job or 2X day training, i.e marathon, contest etc.)


We will call this variable the ActMP in the proceeding formula. Please select the correct formula for your gender:


Male
TDEE = (66 + (13.7 * WeightInKg) + (5 * HeightInCm) - (6.8 * AgeInYears)) * ActMP
Female
TDEE = (655 + (9.6 * WeightInKg) + (1.8 * HeightInCm) - (4.7 * AgeInYears)) * ActMP



My Results
TDEE = (66 + (13.7 * 78) + (5 * 180) - (6.8 * 23)) * 1.55
TDEE = (66 + (1068.6) + (900) - (156.4) ) * 1.55
TDEE = 1878.2 * 1.55
TDEE = 2911.21


The Katch-McArdle Formula for Basal Metabolic Rate

This formula is set apart from the rest in that it takes your lean body weight into account. It is regarded as the most accurate, but it also puts the most demands on you in terms of input. Because the lean body mass variable is explicit, the same formula works for both males and females.

See the above table for the activity multiplier (ActMP).


TDEE = (370 + (21.6 * LeanMassInKG)) * ActMP



My Results
TDEE = (370 + (21.6 * 64)) * 1.55
TDEE = (370 + 1382.4) * 1.55
TDEE = 1752.4 * 1.55
TDEE = 2716


The Weight Watcher's Method

Weight Watchers, which helped me burn ~50lbs and keep them off for over a year (though I have never paid them a cent, I just followed their principles and borrowed some literature from a friend who went into their program), keeps the calories down to an astonishing low.

Their patented formula takes into account the calories, fat grams and dietary fiber grams to assess a value called a "point". Then, given your weight, you are put in a group which allows you to have a certain number of points.

First off, the table of points to weight is as follows:


Less than 150 lbs, 18-23
150-174 lbs, 20-25
175-199 lbs, 22-27
200-224 lbs, 24-29
225-249 lbs, 26-31
250-274 lbs, 28-33
275-299 lbs, 29-34
300-324 lbs, 31-36
325-349 lbs, 31-36
More than 350 lbs, 32-37


The points formula is as follows (note that you never need to calculate it if you sign up, they provide you with all the lists you need):


Points = (Calories / 50) + (FatGrams / 12) - (min{DietaryFiberGrams,4} / 5)

Note: min{DietaryFiberGrams,4} means to take whatever is lower, the number of dietary fiber grams or 4, and insert it into the formula.


Running the Weight Watcher's formula through one of my diet days in my spreadsheet gives me around 36 points for 1300-1450 calories, depending on how much dietary fiber I'm consuming. As a 172lb guy, I'm supposed to be consuming between 20-25! Where would that put me? At around 1,000 calories per day. Perhaps this is why I reached my weight goal last year and I still felt I had something to lose?


Bibliography


Marcus has a sticky post in the Nutrition for Weight Loss messageboard which discusses the BMR formula.

Fitren Calorie Calculators Article (http://www.fitren.com/res3art.cfm?compid=18&artid=46)

The Body Sculpting Bible for Men (http://www.amazon.ca/exec/obidos/ASIN/157826085X/702-0944400-2178425)

Weight Watcher's formula (http://www.healthyweightforum.org/eng/articles/weight_watchers_points/)

Great Post! :tu:

I just saved this information on my system, but I think this thread deserves a sticky!!

Good Post Sludge :tu:

Did you determine which equation seemed to be the best?

I did a similar thing when deciding what equation to put in my Nutrition Guide. I chose the Harris Benedict Formula because it generally gives a higher more conservative figure. I thought its best to start off eating a little bit to much than eating too less. Then you can just guage your progress and adjust as required and then through that kind of experimentation you can find out exactly how many cals you should be eating. I dont think any formula can tell you accurately how much you should be eating so its up to you to alter it to suit your personal needs.

I'd be interested to see what formulas are used most. Maybe you could put a poll up or something.

Marcus :tucool:

I have been using my BMR as a guide, not long enough to accurately track results, but calculating with the formula that uses Lean Mass came out 300 calories less (I had my lean mass measured at the gym with extensive calipers, seemed to be pretty accurate). Any thoughts as to which one might be more accurate? I'm eating about 1900 cals right now but thats with aggressive weight loss (2.5 lbs per week). Thanks.

Good Post Sludge :tu:
Did you determine which equation seemed to be the best?


I did mention that the Katch-McArdle is regarded as the most accurate. There is a good tradeoff between what you need to plug in to the formula and what you get out.

I think you did the right thing with your nutrition guide by hammering home one formula. It doesn't make sense to inundate the readers with multiple solutions when they're starting out.


I dont think any formula can tell you accurately how much you should be eating so its up to you to alter it to suit your personal needs.


I've heard of software that varies your caloric maximum based on your previous intake, using SOME algorithm or heuristic. I'd be interested to see how it arrives at these results, and if the formula is more accurate than checking if it's an even numbered week. I haven't been able to turn up any info on this yet, though.

... i.e. my food intake, energy expenditure, etc, here is what I have:

As a 200 pound, 12-percent body fat male 5'10", I require 3000 calories to maintain my weight WITHOUT FACTORING EXERCISE. In other words, if I burn 400 calories, then my maintenance is 3400 calories.

When I increase my protein, that can jump as much as 200 i.e. I could add 200 calories of protein and still maintain that weight.

In order to lose 3 pounds per week, I had to create a deficit of (3500 / 7) x 3 = 500 x 3 = 1500 calories. This would mean eating 1500 calories, but then add in exercise of around 500 calories per day, and you come to 2000. This is EXACTLY what I averaged over 12 weeks to drop from around 210 pounds in May 2003:

http://www.naturalphysiques.com/gallery/jeremytransform/may172003

to 178 pounds in August.

Of course, I did not use a formula to come up with this - I used the DietPower software which learns your metabolic rate through your activity (I write about it here: http://www.naturalphysiques.com/news/VIi001xuqs.html#six ).

Using traditional formulas, it would be:

Basal Metabolic Rate:

http://www.naturalphysiques.com/tools.php?itemid=20

1865

Then you usually have an activity multiplier, with sedentary at 1.2 and professional athlete at 1.8. I would choose very active (1.6)

Let's try that out:

1865 x 1.6 = 2984.

In my case - LO AND BEHOLD -the equations work.

However, in many other cases, I've had people be off by up to 400 calories either way from the equations.

Jeremy