The Importance of Body Composition

Females normally carry around 5% more body fat than men

Females normally carry around 5% more body fat than men

Forget about how much you weigh! Unless you are a competitive cyclist or an athlete trying to compete in a certain weight class then it really doesn’t matter. It is not an indiction of health, fitness level or attractiveness.  What is important is your body composition. This means the ratio of lean body mass (bones,muscles and organs) to body fat.

Last October I worked out twice a day, six days a week (the advantages of being young…lots of free time!) with one day a week off and I ate very clean, healthy food and yet, by the end of the month,  I weighed a pound more than when I started!  Most people may think that this is a negative thing because they are so obsessed with bodyweight. What they should really be obsessed about is body composition! How much fat and lean body mass do I have? This is the most important point. Only when this is taken into account and measured do you get a true picture of the level of success you have achieved. For example, in October I actually lost 6 pounds of fat and gained 7 pounds of muscle. Now that is a good result (it took a lot of work!) but with the conventional bodyweight oriented thinking one would be none the wiser!


You need to forget height and weight charts and BMI (Body Mass Index) and focus on your fat percentage. That is a very good indicator of health, fitness level and attractiveness. A person with 35% body fat is going to look like a beached whale.  A person with 8% body fat is going to look like model or professional athlete.  Having a low percentage of body fat can give you a tremendous advantage if you are involved in sports.

Let’s take a fairly average man with 20% body fat who weighs 200 pounds (91kg). He has 40 pounds of fat.  Let’s say that 10 pounds of fat is vital for his existence so that leaves him with 30 pounds of fat that he is carrying around. Imagine cycling around with a backpack containing 30 bags of sugar!  That’s going to slow you down quite a bit isn’t it? Let’s do a quick bit of [very rough] maths.
One pound of weight can cost you up to 6 seconds per km when going uphill. So let’s see how much quicker  our fairly average man could be if he lost those 30 pounds of fat.  Let’s assume he is doing a 10km climb with an average gradient of 5%.
So for each KM he travels our fairly average man is being slowed down by his 30 pounds of fat so that will cost him:
He is 3 whole minutes slower per kilometre due to his excess fat! So, on this 10km climb he  could be up to 30 minutes slower than he would be if he was at his ideal cycling weight.
That’s why it’s quite funny/ridiculous seeing hugely overweight Mamils on incredibly light carbon frame bikes!
An incredible specimen of the Mamil family

An incredible specimen of the Mamil family

The advantage of regularly measuring your body composition is that you get feedback on your workouts. If you are losing fat or gaining lean body mass then keep doing what you’re doing! If you have gained fat or lost lean body mass then you need to rethink your strategy. I recommend measuring your body composition once every 7 to 10 days. To do this I use a Tanita Body Composition Monitor. They aren’t too expensive and are accurate enough for home use.
If you are serious about losing body fat you need to be measuring your body composition. If you don’t then you might as well admit to yourself that changing your physique and improving your health  is not one of your primary goals at this stage of your life. 

You could spend years not really getting anywhere unless you have a way of measuring your success. That’s why we love Strava :) If you can track something, you can improve it.

EDIT: I found an even better graphic than the one above to show the way people look at different body fat percentages:

Bodyfat Comparison


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