Why Cardio Isn’t as Effective as Weight Training for Losing Fat

 Benjamin J Marshall


Why cardio isn’t as effective as weight training for losing fat

If you are newish to fitness and want to lose some weight the go to answer is start running yes?

NO! Let me talk you through why cardio will not help you lose weight.

Cardio burns more calories?

So there is an idea that cardio burns more calories than weight training however this is not the case. The theory is that LISS (low intensity steady state) training such as going for a run for an hour will burn a constant amount of calories for that hour, whereas weight training is broken down into sets where rest is included between each set, therefore in a hour spent in the gym weight training around half of it will actually not be lifting weights. Therefore you burn more calories doing cardio? …..No not so.

Think about the energy required when taking 20 paces jogging, and then compare that to the energy needed to do 20 squats with resistance weight. The squats will require a lot more energy to be used and you will find that you can easily match your energy output over the hour even including the rests. Another point is that cardio burns calories only whilst you are doing it where as weight training requires your body to use energy to repair and grow the muscles that you have broken down which continues after you finish your exercise.

Ben Marshall

Running or Cycling are the same as working out your legs

No sadly they are not and there are three reasons for this:

Firstly: the range of motion and targeted muscles- when running your range of motion is actually very small, you are not performing a lunge every step. So the muscles do not have to engage as much as they are not working through a whole range of motion. When a muscle is put through a whole range of motion the entire muscle is stretched and then contracted requiring a lot more energy, when a muscle is not required to perform an entire range of motion the contraction is not as great and less energy is required.

Secondly: Targeted muscles used- You are doing the same motion over and over and over again when performing cardio, think about an elliptical or sep machine where you literally cannot change your range of motion. This means that some muscles are not being worked in the same way as other muscles, cycling is far more inclusive as the range of motion is bigger but you cannot change which muscle group you are targeting. This can lead to muscle imbalance in the legs and is not effective as a whole leg workout even if you really “feel” it.

Thirdly: the muscle fibres engaged – with cardio work you are targeting your slow twitch muscle fibres as they are responsible for muscle endurance. And you then neglect the fast twitch muscle fibres which are used for resistance explosive training and are also bigger.

The exception here is sprinting which uses your fast twitch muscle fibres but although that might fall underneath the umbrella term of “running or cycling” sprint training is actually not cardio and is actually more plyometric and explosive resistance training,

“You can target your fat in a Fat Burning Zone in cardio ….”

This is an out dated term which has been exploited and blown way out of proportion. The theory behind it is that lower intensity exercise burns a higher percentage of calories from your fat stores rather than you glycogen stores. This however does not mean you burn more calories!

Yes you might burn a larger percentage of fat calories but your overall calorific burn will be much, much lower. You may burn 200 calories and 60% coming from fat in a “fat burning zone”, but you will burn 400 calories with only 40% coming from fat outside of this so called “zone”. The ideal is that you burn glycogen calories when working out because it is stored locally in the muscle and is used as energy when that muscle is use. People get confused thinking that they only want to burn calories from fat when working out. However don’t worry about this. Focus on your total energy balance for the day and as long as you are in a deficit you will lose weight.  It is much better to use your glycogen as energy when you are exercising and your fat stores for the rest of the day, because that is what they are designed to do, slow release energy!

But you can count how many calories you burn doing cardio?  

No quite, you can measure an output which can be consistent for you as an individual but this does not actually equate to calories necessarily.

In a number of studies by the University of California it was concluded that cardio machines over-estimate calorific expenditure, and sometimes it is by a lot! Treadmills can give you up to 42% extra calories burnt, even those that take into account your weight can only give you an average covering the distance over time and does not take into account the actual effort.

So you can not equate burning 800 calories an hour on a treadmill to put you into an 800 calorie deficit.

Now this doesn’t mean they are useless, but you have to take it as a non value measurement. For example if a someone burns what the treadmill says is 400 calories it does not actually matter what this represents , but as long as the they continue to hit this number they will continue to burn this same unknown calorie number.

If they want to increase weight lose they just need to increase this number so if the treadmill now reads 800 calories although they might not be actually burning 800 calories as they have doubled this unknown number therefore doubling calories burnt.

And the final nail in the coffin…Comparison 

Consider two people one of whom loses 10 pounds via cardio and the other loses 10lb via weight training, you think that they will look the same? No they won’t. The person only using only cardio will lose 10lbs of body fat as well as muscle. The person using weight training will actually lose considerably more body fat as although their weight will have dropped 10lbs they will have also gained muscle which adds weight so to lose 10lb they will potentially lose more like 15lbs of body fat as well as building a more athletic body.


I am not saying you shouldn’t do cardio, it definitely has its place in a healthy lifestyle but what I am saying is please do not jump into the idea that cardio is the only way forward in losing weight. Too many people fall into this trap and are then disappointed and disheartened with their results. If you want to look like a long distance runner then train like one, however if this isn’t your goal then this isn’t how you should be focusing on training.

Take your goal and find the best way to achieve it and in the case of fat loss this is not by doing endless hours of cardio.


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