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## Maintenance Calories: How to calculate them>

Posted Wed 13th Feb 2013 7:19 PM by Dan Britchford in Nutrition

Probably a post I should have done earlier, but in response to a comment on a previous post (and the lack of formatting my comments system seems to allow atm) – here’s an article on how to calculate a good estimate of your Maintenance Calories.

There are a few ways to calculate your maintenance calories, but the easiest method you can do at home would be using a formula.

There are three main formula usually used; the Harris-Benedict formula, the Mifflin-St Jeor formula, and the Katch-McArdle formula. For most people I would suggest using Mifflin-St Jeor, even though it tends to overestimate maintenance calories in the overweight. But if you have a good estimate of your body fat level and are relatively lean (~6-14% body fat), use Kath-McArdle, as it is the most accurate under those circumstances. Harris-Benedict is pretty outdated, so I haven’t included it.

#### BMR formulae

Mifflin-St Jeor:
MEN: BMR = [9.99 x weight (kg)] + [6.25 x height (cm)] – [4.92 x age (years)] + 5
WOMEN: BMR = [9.99 x weight (kg)] + [6.25 x height (cm)] – [4.92 x age (years)] -161

Katch-McArdle:
BMR = 370 + (21.6 x LBM)

*where LBM (Lean Body Mass) = [total weight (kg) x (100 – bodyfat %)]/100

These will calculate your rough Basal Metabolic Rate (BMR), and you then need to multiply this by an activity factor to get an estimate of your level of Maintenance Calories.

#### Activity multipliers:

1.2 = Sedentary (desk job, and not much exercise)
1.3-1.4 = Lightly Active (light daily activity AND light exercise 1-3 days a week)
1.5-1.6 = Moderately Active (moderately daily activity AND moderate exercise 3-5 days a week)
1.7-1.8 = Very Active (physically demanding lifestyle & hard exercise 6-7 days a week)
1.9-2.2 = Extremely Active (you’re an athlete in training all the time or have an extremely physical occupation)

Multiply whatever result you got using one of the BMR formulae by the correct activity multiplier for you (if in doubt, pick a lower multiplier), and that will be your estimated daily maintenance calories.

In reality, the number is just an (educated) estimate and I recommend checking on how you progress on those calories and then tinkering (upping or lowering) based on the results you see over a 2-4 week period.

### An Example

Just in case the numbers and formulae are throwing you, here’s a quick example using both formulae.

The individual in this example is a 21 year old male, who is 6ft tall, weighs 70kg, and has a body fat level of about 9%.
The individual also works out 4 times a week, and has a desk job.

Mifflin-St Jeor

BMR = [9.99 x (70)] + [6.25 x (182.88*)] – [4.92 x (21)] + 5
= 1743.98

*6ft in centimetres is 182.88

looking at the activity multipliers, the individual probably sits between lightly active, and moderately active. Let’s choose the higher end of the lightly active multiplier for this case (x1.4) – but you could even go right down the middle and use 1.45 as a multiplier.

So 1743.96 x 1.4 = 2441.572

therefore, this individual’s daily maintenance level is 2442 calories per day, according to the Mifflin-St Jeor formula.

Katch-McArdle

with this formula, I like to calculate LBM (lean body mass) first, like so:

Lean Body Mass = [(70) x (100 – (9))]/100 = 63.7 kg

and then, add this into the Katch-McArdle formula;

BMR = 370 + [21.6 x (63.7)] = 1745.92

The activity multiplier will be the same, as it is the same individual, so;

1745.92 x 1.4 = 2444.288.

maintenance level of 2444 calories per day, according to the Katch-McArdle formula.

In this case, you would use the Katch-McArdle estimate (not that there is any significant difference), because you have a good estimate of the individuals body fat percentage.

Hope this helps!

– Dan