Low intensity fasted cardio accelerates fat loss… or does it? 🤔
It’s been long believed that participating in low intensity cardio before breakfast increases fat oxidation. Therefore, removing more body fat than non-fasted cardio.
I’ve seen it all over Facebook. Especially now, during lockdown. People out early doors for their hit of “fat blasting” cardio.
But what is the logic behind fasted cardio?
It’s true that fat oxidation occurs at a faster rate when insulin is low. Insulin is of course low first thing on a morning (fasted state).
It’s also true that low-moderate forms of activity predominantly use fat as an energy substrate. Especially longer durations of 45-60 minutes (the “fat burning” zone).
So, 1 + 1 should equal a “fat burning machine”, right?
It certainly sounds sexy.
“Get in tune with your fat burning hormone and incinerate fat in just 45 minutes”
How many people do you think would use this slogan? (lol).
But here’s the thing;
Sexy doesn’t make you sexy. Sure, it sounds plausible and to be fair, completely logical.
But there’s one significantly missing factor here;
Fasted cardio is just energy OUT.
So, maybe you DO burn fat as you hit the roads at 6am before your day begins.
But… at some point during the day you will in fact, need to eat.
Food equals energy in.
Therefore, replacing this lost energy.
Energy balance is what dictates fat gain/fat loss.
In this study, 20 females were assigned a hypocaloric diet (calorie deficit). Ten subjects were assigned to a fasted training group and the remaining ten ate before training. Both showed a significant loss in weight, but no differences were apparent between the two groups.
Indicating fasted cardio makes no difference to weight loss.
Let me give you an example.
Jessica wants to lose a little body fat. We know (because we’ve just done all her fictional calculations) that Jessica’s maintenance level is 2000 calories per day.
So, for Jessica to lose weight she needs to be in a slight deficit of around 1600-1800 calories per day (200-400 deficit)
Dave, her trainer, hasn’t bothered to do her calculations. Instead he’s told her she needs to get up and do fasted cardio before work.
He’s given her the low down on insulin levels being influenced by blood glucose. Blood glucose is at its lowest in the morning due to the night time fast. Therefore, morning fasted cardio will get her lean and stripped physique.
Jessica doesn’t really want to know the science; she just wants to lose some body fat and feel fabulous.
But she trusts Dave knows his stuff. Afterall he sounds super smart with all the big words he uses.
Three weeks past and Jessica still hasn’t lost any weight. She’s getting tired of the fasted cardio and would rather just get up and have her breakfast like everyone else.
“Surly fat loss should be this hard?” – She asks herself.
As it turns out, Jessica is still consuming 2000 calories worth of food every day. Even with the fasted cardio Jessica still isn’t in a deficit. In fact, if anything she’s hungrier.
What Dave didn’t mention was that her daily caloric intake was the ONLY thing she needs to consider.
Jessica could fast all day BUT if she still consumes 2000 calories that day it won’t make one little bit of difference. Because she’s still consuming what it takes (2000 calories) to keep her the same weight.
Now let’s say Jessica doesn’t do fasted cardio. Instead she gets up and has her breakfast and goes about her day. Only this time we’ve taken her calorie intake to 1700 (300 deficit).
Over the proceeding weeks and months Jessica gradually loses the weight she wants to. She’s happy she can live a normal life and doesn’t need to do crazy “sexy” stuff to lose weight and feel great.
Jessica now understands that energy balance is the factor. More specifically for her, a deficit of energy. How she creates that deficit is up to her. She can reduce the intake. Increase her output. Or get a manageable balance between the two.
She may decide that morning cardio she actually enjoys. It makes her feel good and has her motivated for the day. And she’d much prefer to burn 200 cals going for a run than taking 200 cals away from her daily diet.
And if she ate a little something before hand it might give her a performance advantage.
There’s no right or wrong way – Do what you enjoy and makes you happy.
But just remember one thing;
Sexy doesn’t make you sexy. If it sounds complicated or too good to be true, it’s just that, too good to be true.
The reality is that fat loss is super simple in terms of methods. The harsh reality is that it takes commitment and consistency. Fasted cardio isn’t going to make a single bit of difference.
And with that, here’s the “unsexy” reality of all you need to be concerned about:
Energy in Vs. Energy out.
Get this right and you’ll ace results.
Please feel free to comment below.