Cardio has long been the go-to form of exercise for new gym members and people trying to lose fat.
Cardio machines are marketed to seem like they burn insane amounts of calories, they’re typically shoved right in front of your face when you first walk into the gym, and as such, they get a lot of use. There’s absolutely nothing wrong with that, by the way. The benefits of cardio certainly are a part of the overall picture of health we aspire to have.
But is it the best way to lose fat?
In the short-term, possibly.
I’ll come back to why this is the case, but first you need to understand the mechanisms at play when your body is losing or gaining weight.
When you’re trying to lose fat the first thing you need to do is create an energy imbalance. You need to burn more energy than you consume. This energy is measured in calories.
So if you burn 3000 calories per day but you only eat 2500 calories, you will lose weight. The opposite is true if you eat 3000 calories per day but you only burn 2500 calories, you will gain weight.
So that’s the most important thing to know when looking to lose fat. And you can achieve your desired energy imbalance without ever doing cardio! If you are quite active already, maybe you work an active job, or you go for regular walks and you lift weights, you might already burn enough calories to create that energy imbalance.
If this is you and you don’t like staring at a monitor for 45mins every day, cardio doesn’t make much sense. You’re already burning enough calories and contributing to your fat loss goals. By all means, if you enjoy cardio, go for it! Just know that it’s not necessary to create an energy deficit and lose fat.
If you don’t burn enough though, should you do cardio?
I am always an advocate of long-term, sustainable fat loss. And the key to long-term, sustainable fat loss is muscle growth. Lifting weights and getting stronger will undeniably give you more long-term success and health than most forms of cardio.
If you can build muscle and speed up your metabolism, you give yourself the greatest chance of permanent fat loss. You see, if you hit the treadmill for 45mins you might burn 400 calories, for example. As soon as you step off that treadmill though, the benefits pretty much end straight away. You aren’t burning any extra calories because of the work you did; in fact, you’re probably burning less now that you’re a little fitter. Your body, being the adaptation machine that it is, actually becomes more efficient with its energy use as you get fitter.
It takes a lot more energy for someone that has never ran 5km before than it does for someone that runs 5km every day. This energy is calories burned. So, by becoming better and better at cardio, you actually lower the number of calories your burn per session. Once again, there’s absolutely nothing wrong with that in a fitness and activity sense; if you become more fit you are much more likely to reap other benefits and generally live a happy and healthy lifestyle.
From a fat loss standpoint though, you are lowering the number of calories you can burn during the day and if you were to ever stop doing that form of cardiovascular exercise, you immediately lose 400 calories (just as an example) worth of energy expenditure. This is a big contributor to yo-yo diets and people gaining back weight. You go on a massive health-kick, start smashing gym sessions 3 times a week but when you inevitably stop, you gain all the weight back.
Because you never created a state for your body to naturally burn more calories. You were forcing your body to burn more calories through excessive gym sessions. As soon as you stop, you are no longer in an energy deficit and end up gaining weight as a result.
So how do you give yourself the best chance of permanent fat loss?
By lifting weights!
When you lift weights, you continue to burn energy after the session during your recovery and growth phase. You also help to speed up your metabolism over time because of the muscle that you’ve built.
Think of it like 2 different cars.
In one garage you’ve got a tiny little 4 cylinder that’s extremely efficient and cheap to fill up with petrol. In the other garage is a big truck with a V8 engine. It’s expensive to fill up with petrol and burns through it quite quickly.
When you stick to cardio only, you’re never building your body’s ‘engine’. Sure, you’re efficient, but that means you need very little food to maintain your current size, 1500 calories for example. If you were to overeat and consume 2500 calories, you’re already starting the fat gain process. Not only that, if you want to lose fat, you’ve got very little wiggle room to play with. Dropping to 1000 calories can be very difficult to sustain and often causes you to binge on large amounts of food and eventually give up on your goals.
Essentially, your metabolism becomes the tiny little 4 cylinder car.
On the contrary, if you lift weights and build a big engine (or metabolism) like the truck, you can eat 2500 calories daily and still be maintaining. Not only do you burn more energy simply to maintain your shape, but you can more easily manipulate your food intake to lose fat; you’ve got more wiggle room! You can drop your calories down to 2000 and lose fat while still eating a good amount of food.
That’s the key to long-term success, get to a point where you can eat a good amount of food without restricting yourself completely. Unfortunately, cardio doesn’t give you that benefit. It can be a great tool to add in some extra calorie burning in the short-term, but aren’t you in it for the long haul?