top of page

Cardio for Fat Loss

Writer's picture: Lewis RobinsonLewis Robinson

Updated: Jan 30

Myth 1: Do Cardio before Weights ❌


This Mythical Tale begins when I came across Posts online with regards to whether Cardio should be done before, after or on separate sessions to lifting.


What I witnessed was Influencers (on this occasion rightly so for a change) saying that Cardio should never be done BEFORE lifting weights but AFTER, and at this point it should be Steady State and LOW intensity.


So FAR so GOOD.


But what was their reasoning? 


Well put simply, it was so you have enough energy for lifting weights. While this isn’t incorrect, there is a little bit more to it.


Here is why you should do Cardio AFTER Weights IF your goal is for FAT Loss - (for any other reason it should be left for another time or day)....


  1. When you do Weight Training the main fuel source is Carbohydrates that is broken down into Glucose. 

  2. Your Glucose Stores are only a Finite Supply whereas Fat Stores are more Extensive.

  3. Cardio Training has TWO Fuel Sources, Carbs and Fats.

  4. The body will always burn Carbs First in the form of Glucose because it is a lot easier and requires very little Oxygen.

  5. Cardio will burn Glucose before reverting to Fat, which is harder to break down.

  6. So by putting yourself on a treadmill or bike first off will mean that all you are using are your Glucose Stores (for up to as long as 20 minutes) before the Body attempts to switch to Fat Stores….

  7. So Cardio before Weights is an ABSOLUTE NO NO!

  8. You will have expended all the necessary Glucose you need for lifting and your body will be trying to draw on Fat Stores in an environment (Weight Lifting) where you cannot generate enough Oxygen in the system to Utilise Fat for Energy.

  9. The movement of Weight Training however (where you are in an Anaerobic State) will ensure that you are using up Glucose stores first and foremost as they were intended to.

  10. By then going onto Cardio with your Glucose Stores depleted, your metabolism is elevated by up to 300% and your body is then in a position to draw on its Fat Stores where you will burn up to 3x more Calories from Fat.

  11. However, you will need to keep your Heart Rate (HR) low within your Ideal Fat Burning Zone, so Slow Steady State Training is essential.



Myth 2: Cardio doesn’t burn Fat Stores, only Dietary Fats ❌


NOW for the Controversy and the Bull Shit that comes NOT JUST from Influencers but from the Mis-Informed that either follow or simply think they know better….


After backing one Influencer and their post, their reply to me was….

  1. Firstly Lewis, I’m not an Influencer I’m a Coach 😳

  2. You are incorrect. You only use “Dietary Fats”  for Fuel in Cardio not Fat Stores. 🤦

  3. Fat Stores are only used when one is in a Calorie Deficit 🤣

  4. To know the difference is the same as to know the difference between Fat Oxidation (Break Down of Fats to be stored) and the process of Fat Burning 🤷


This said Influencer really did not know what he was talking about and not after long was back peddling to stop himself from tripping up and sounding the fool….🤡


Facts are:

  1. Cardio DOES utilise FAT STORES for Energy (under certain Aerobic Conditions)

  2. Dietary Fats take up to 8 Hours to be Oxidised so cannot be immediately called upon for energy.

  3. Yes, being in a Calorie Deficit does help to draw upon Fat Stores but that doesn’t take away from the fact that they are also used in Exercise. 


This Influencer was too far down the Garden Path by now to retract what he was saying so tried to come back by asking if I was referring to Heart Rate Fat Burning Zones. 


Fuck off Pal, that boat has sailed and you’ve been exposed. All of this after I had backed the fella as well 🤣🤣🤣….


Which brings me onto the FINAL MYTH connected with all this….


Myth 3: Cardio is a waste of time FOR FAT LOSS ❌


I came across another post where the message was, do Cardio for Fat Loss at Speed blah blah blah, Incline Blah Blah Blah for 20-30 Minutes - basically Slow Steady State Cardio.


Great, this seems to be the message of the moment and is correct if it succeeds Weight Training. Except one Response disagreed, the point of their reply was….


  1. You Burn More Calories through running ✅

  2. So it is more effective for “Weight Loss” ✅

  3. Fat Loss is determined solely by choice of Nutrition and being in a calorie deficit ❌

  4. It is inefficient to use Cardio for Fat Loss ❌


This guy was correct in that yes you burn more Calories through Running (Higher Heart Rate etc) BUT you are Burning LESS Calories from Fat. 


He took my argument (of Slow Steady State Training after Weights) for effective Fat Loss to mean that if that was the case then everyone could just sit on their arse and burn fat - referring to this belief that a Calorie Deficit was the only way.


He really believed that burning more calories overall through running, coupled with lifting weights, being in a calorie deficit and having sound nutrition was the ONLY way to burn fat and lose weight long term - I don’t think he understood either that fat loss and weight loss are two totally different things. 


And he certainly didn’t get the idea or concept of Potential Energy (used when sedentary) compared to Kinetic Energy (required for movement). 


I'm not claiming he was incorrect, and he grasped the science regarding how cardio at specific levels influences the fuel used - RQ Testing, VO2 Max, etc., but he was unwilling to accept my science-based argument ☝


So in Conclusion,

 

  1. Cardio isn’t a waste of time if your goal is Fat Loss. As long as it is AFTER Weights you will draw on Extensive Fat Stores.

  2. Dietary Fats have nothing to do with Exercise

  3. A Calorie Deficit alone will not utilise Fat Stores (although it does help)

  4. For FAT LOSS always do Cardio AFTER Weights

  5. For all other Fitness Goals, Cardio should be done at a different time of day to lifting (with enough time to Refuel) or on a totally different day.


Feel Free to leave comments and Feedback 💪


And if you would like to know what your Fat Burning Training Zone is or what your Calorie Deficit you need to be in then drop me an email - info@lewisrobinsonfitness.com


Blink and you'll "Myth" it....



9 views0 comments

Recent Posts

See All

Comments

Rated 0 out of 5 stars.
No ratings yet

Add a rating
  • Instagram
  • Facebook
  • LinkedIn

©2025 Lewis Robinson Fitness lewisrobinsonfitness.com 

bottom of page