What Kind Of Cardio Should I Do To Lose Weight?

If you’re looking to lose weight and get in better shape, the first thing that probably comes to mind is hitting the pavement in a headband and gray sweatsuit and going for a run.

Cue the Rocky soundtrack!

After all, everyone knows that running burns calories, which will lead to weight loss.. right?

You may have also heard about workout classes that use something called interval training. These classes claim that interval training burns the most calories of any exercise and therefore is superior for fat loss.

So which one should you do?

I’ll answer that very question in this article. By the end, you’ll know which kind of cardio is best for fat loss, and I’ll give you some practical tips on the best way to perform your cardio.

Let’s get started!

Weight loss crash course

Before we get into which method of cardio is better for weight loss, it’s important to understand how we lose weight.

When most people talk about weight loss, they are really referring to fat loss. There is a difference, and from here on out I don’t want to use them interchangeably.

Weight loss can come from muscle, bone or fat.

Fat loss comes strictly from body fat.

I’m guessing if you want to lose weight, you want it to come from fat, and not from muscle or bone. Keeping muscle mass as you lose body fat will help men keep their chest and arms chiseled and females look toned and keep their butt as the scale goes down.

In order to lose fat, you need to be in something called a calorie deficit. 

A calorie deficit is simply an energy imbalance.

On one side of the energy scale you have the amount of energy you take in every day. This energy comes in the form of calories from the foods and drinks you consume.

The other side of the energy scale is the amount of energy in calories you burn every day. It is called your Total Daily Energy Expenditure (TDEE). It can be broken into four categories:

Basal Metabolic Rate (BMR)- This is how many calories you burn every day from doing basic functions you don’t control like breathing, thinking, and keeping all of your organs functioning. If you were in a coma, this is the amount of calories you’d burn.

Non-Exercise Associated Thermogenesis (NEAT)- You burn calories when you fidget, take out the trash, or do any other unplanned activity throughout the day. This is called your NEAT.

Exercise Associated Thermogenesis (EAT)- This is the amount of calories burned because of planned exercise (like running or interval training)

Thermic Effect of Food (TEF)- It takes a certain amount of calories to digest food, which is what TEF consists of.

One way to tip the scale towards a calorie deficit is to eat less calories.

Another way to tip the scale towards a calorie deficit is to burn more calories through exercise (AKA increase your EAT), which is what we’re going to cover next!

Steady state cardio vs. interval training

Ladies and gentlemen, in the red corner we have running, biking, walking, using the elliptical or any activity that you can perform at a steady pace for a given amount of time! Introducing.. steady state cardio!

And in the blue corner, we have performing short bouts of high effort exercise (like sprints, battle ropes, or stationary biking) followed by longer periods of low intensity recovery or complete rest! Please give it up for.. interval training!

When comparing the two, both have pros and cons when it comes to burning calories.

Steady state cardio is performed at a relatively low intensity. This means that you can perform more of it, more often without it interfering with your recovery or weight training workouts. 

Because it must be performed at a high intensity, interval training is much harder than steady state cardio. To reap the calorie burning rewards of an interval session, you have to train hard. A truly intense interval session can leave you frantically searching for the nearest trash can to puke in. That means you won’t be able to perform interval training very often or for very long, and it can negatively interfere with your strength training. 

A unique benefit of interval training is something called the afterburn effect. The afterburn effect (technically called excess post exercise oxygen consumption, or EPOC for short) is a phenomenon where your body continues to burn calories hours after intense exercise (1).

So.. which one will help you lose the most fat?

And the winner is..

Ladies and gentlemen, the heavyweight champion (of cardio that helps you lose weight) IS..

Neither.

What?!

The majority of research shows that without changing your diet, performing cardio is highly unlikely to lead to any meaningful fat loss.

How can this be? I thought cardio burns calories?!?

Even though both types of cardio burn calories, the amount of exercise you’d need to do to perform to get any type of meaningful fat loss is much more than you probably have time for.

One study, which controlled for calories eaten (meaning the fat loss came strictly from the steady state cardio), showed that about 100 minutes of steady state cardio per day resulted in an average of 11 pounds of fat loss in 90 days (2).

I don’t know about you, but I certainly don’t have time to do 100 minutes of cardio per day! Not to mention the fact that most people could probably lose the same amount of weight or more over 12 weeks by restricting their calories.

The amount of calories your smartwatch says you burned is probably not accurate, either. Research has shown that most wrist-worn fitness trackers don’t accurately measure how many calories you burn (3). 

That’s one of the reasons I don’t recommend clients try to track how many calories they burn. It’s not going to be accurate and honestly it really doesn’t matter that much.

What about the afterburn effect? I thought interval training burned calories even after you finish the session?

It’s true that interval training at high intensities can burn more calories after the session than steady state cardio, but it’s probably not a meaningful amount. 

In one study, the afterburn effect was a whopping 110 calories in the three hours following an intense interval training session (4). That’s about the equivalent of a medium banana. 

The researchers also made a note that the interval training wasn’t “well tolerated” by the subjects, with three of them having to leave the study because of nausea, lightheadedness and vomiting! 

These conclusions are all reflected in a recent paper looking at 54 different studies comparing interval training and steady state cardio.

The average amount of weight lost over 12 weeks was just about a half a pound (5).

The authors concluded that exercise, regardless of whether it was interval training of steady state cardio, had a very minor impact on fat loss. Even though cardio burns calories, creating a calorie deficit through diet is a much more time efficient strategy.   

What this means for YOU

I’m NOT saying that you shouldn’t do cardio for fat loss EVER. I’m saying that most of the time, changing your diet is the best way to lose fat. In some cases though, cardio can help accelerate fat loss. 

Let me explain.

Let’s say you’ve been dieting for a few months. You’ve lost some weight, your calories are already low, and you’ve stalled out on fat loss progress. The thought of lowering your calories even lower makes you want to drive your head through a brick wall.

Performing some type of cardio makes sense for you. You can keep your calories the same and create a slightly bigger calorie deficit through exercise. This can help break you through that fat loss plateau.

On the other hand, let’s say you’ve been in a muscle building phase and now you’re looking to lean out for the summer. 

You probably don’t need to incorporate a bunch of cardio right off the bat to start losing weight. You’ll be able to keep your calories relatively high while losing body fat because your metabolism is higher.

How to incorporate steady state cardio for fat loss

If you’re looking to add in steady state cardio, a good place to start is 30 to 60 minutes two to three times per week. I would recommend performing it on days that you don’t strength train. So if you strength train on Monday, Wednesday and Friday, you’d perform your steady state cardio on Tuesday, Thursday and Saturday.

Remember that you should be going at a pace that you can maintain for the entire duration of the session! 

I would also recommend changing the equipment you use for steady state cardio every few weeks. Don’t just go for runs or use the same piece of equipment- it’s a great way to end up with overuse injuries.

How to incorporate interval training for fat loss

Generally, you’re going to want to keep the work to 10-30 seconds for interval training. This is so you can push yourself hard. If you try to do more than 30 seconds of work, the intensity will drop and defeat the entire purpose of interval training!

You also need to be resting long enough. A 1:2 work to rest ratio should be the minimum. You might think that less rest is better and it will lead to burning more calories, but the issue is you won’t be able to work hard enough during the work portion of the interval. 

There are two ways I like to program interval training with clients. The first way is a fixed work to rest ratio. For example, you perform 15 seconds of work followed by 45 seconds of rest for 10 rounds.

The second way is to use your heart rate as a guide for how long to work and how long to rest. The downside to this method is you’ll need a heart rate monitor that straps around your chest. You can use a smartwatch, but they aren’t as accurate as a chest strap.

I like to have clients work up to 85-95% of their estimated maximum heart rate, and then recover to about 70%. You can find a rough estimate of your maximum heart rate by subtracting your age from 220.

When performing interval training, you want to pick exercises that are easy on your joints but don’t take a lot of skill. Assault bikes, battle ropes, sled sprints and row machines are all great choices. 

Remember that interval training is much more intense and shouldn’t be performed as often as steady state. One to two days per week is plenty.

You also shouldn’t be doing interval training all year round. Think of interval training as your ace card. You want to save it for when you really need it, like when you’re at the end of a fat loss phase.

One final tip..

Your body generally wants to stay where it is. When you increase your planned exercise by performing cardio, sometimes you will subconsciously decrease your non-planned exercise.

For example, let’s say you do a really intense interval training session on a Saturday morning. You come home, lay on the couch, and binge watch all six Rocky movies.

Okay, okay. Last Rocky reference, I promise.

If you hadn’t done the intense interval session, you wouldn’t have been tired laying on the couch all day. You might have mowed the lawn, or gone to Costco, or 147 other things that also burn calories. The calories you burned during your workout were offset by the calories not burned during the rest of your day.

This is called the constrained energy model (6). 

One way to get around this that I learned from fat loss coach Alwyn Cosgrove is to track your daily steps. Let’s say before you started trying to lose weight you were taking 5,000 steps per day. Once you start incorporating more cardio, your steps drop to 3,000 per day. It’s a safe bet that you’re offsetting some of the calories you burned during your workout by not burning them later in the day.

Even though smartwatches and wrist-worn fitness trackers are pretty unreliable when it comes to measuring how many calories you burn, they can be very useful for tracking steps. If you don’t have one, you can get a cheap step tracker online and keep it in your pocket during the day.

How many steps should you take per day? 7,000 to 8,000 steps have been associated with a lower risk of all cause mortality (7).

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Wrapping up

Hopefully, you’re happy to learn that you don’t need to spend hours and hours running every week to lose weight. 

Likewise, if the thought of interval training makes you want to puke, you don’t need to do it for fat loss either.

If you like doing cardio, then by all means, cardio away! Just know that without changing your diet, it’s unlikely to lead to any meaningful fat loss.