How Much Cardio Should You Do for Weight Loss?

Cardio and weight loss go together like peanut butter and jelly. Gym-loving individuals and protein shakes. Choke-worthy amounts of chalk powder and powerlifters. 

Uh, you get the drift. 

But. Despite the well-known association between the 2, one thing that’s less clear-cut is this: just how much cardio would one need to trigger — and, importantly, sustain — weight loss? 

As always, let’s explore and get to the bottom of this.

Does cardio work for weight loss?

(“What do you mean, ‘Does cardio work for weight loss?’ Of course, it does. The introduction says so.”) 

If those thoughts are running through your mind, please try to smooth out that skeptical expression on your face. Because, yes, theoretically speaking, cardio should 100% result in weight loss based on 2 premises:

1. Being in a calorie deficit (i.e., calories consumed < calories burned) leads to weight loss 
2. Doing cardio increases calories burned 

So, keeping everything constant*, if you:

• Ate at your maintenance calories, then
• Decided to burn an additional 300 calories daily through cardio

*Please keep this assumption in mind; it’s very important.

… you’d expect to chalk up an energy deficit of 300 calories. Because math: neat, logical, and predictable. 

*pops the bubble* But that doesn’t happen in reality. 

Research shows that if you start doing cardio, you’d only lose a paltry 20% to 50% of what you’d expect from the calories you’ve burned. 

Continuing in the spirit of being a wet blanket is this 2021 meta-analysis published in Sports comparing the effects of different cardio types — low-, moderate- and high-intensity aerobic training — on fat loss. 

Guess what they found?

To quantify “wasn’t very effective”, the researchers found the following cardio protocols led to a squint-or-you’ll-miss-it 0.25 kg weight loss after 8 whole weeks:

• 30 minutes of high-intensity aerobic training weekly
• 120 minutes of moderate-intensity aerobic training weekly 

How much cardio for significant weight loss?

OK, but 30 minutes of high-intensity and 120 minutes of moderate-intensity aerobic weekly isn’t much. Right? 

Assuming you work out 3x weekly, they’ll translate to:

• 10 minutes of high-intensity cardio per session 
• 40 minutes of moderate-intensity cardio per session 

So, what if you push the numbers a little higher? 

Would that help give us weight loss figures that are actually worth talking about (because, a reminder: 0.25 kg after 8 weeks is, frankly … sad)?

Well, here’s how much cardio you’d need for significant weight loss, according to a 2000 study published in Annals of Internal Medicine: 700 calories worth. Daily. When the participants did that, they dropped 6.1 kg in body fat after 3 months. 

We know that sounds really impressive, but please read that again. 

700 calories’ worth of cardio! Daily!

That’s how much cardio you need to do for significant weight loss! 

We’ll stop screaming now, but not before giving you an idea of just how ridiculous 700 calories worth of cardio is. If you weigh 60 kg, it’s:

• Cycling at a moderate pace for 1 hour 25 minutes 
• Walking very briskly for 2 hours and 20 minutes
• Having sex for 8 hours and 30 minutes (ummm)

You know what? Here, play with this calculator to find out how much cardio you’d need to burn 700 calories based on your body weight.

… ridiculous, right? Especially that you’d need to do it every. single. day. Otherwise, cardio’s weight loss results are nothing worth screaming about. 

Why, though?

Why is cardio (or at least sane amounts of it) so bad at bringing on weight loss? 

Is it some cruel joke? Is there a higher entity who decided to condemn humans to always fail at weight loss — unless they could do cardio for hours, day after day? Um, no. 

There’s actually a straightforward explanation for cardio’s ineffectiveness for weight loss. 

Now, remember when we mentioned “keeping everything constant”?

It turns out our bodies are terrible at keeping things constant once cardio is in the equation. 

Research shows that the more calories you burn through cardio, the more your body will try to protect its fat stores (traitor!) by burning fewer calories the rest of the day. 

Very sneakily, without you even knowing it, you’d:

… effectively mitigating or even possibly completely undoing the calorie deficit you’d supposedly created through cardio. 

So, is there no point in doing cardio for weight loss?

Wait. Does that mean asking, “How much cardio should you do for weight loss?” is moot? 

Because cardio doesn’t seem to work unless you do unrealistic amounts of it? 

Welllll. Not really. If all this flip-flopping has left you feeling like a pancake on a girdle 🤢, we’d like to say, 1) we’re sorry, but 2) don’t worry; everything will become clear in a bit. 

To recap, sane amounts of cardio don’t seem to work for weight loss because your body ultimately “overrides” any calorie deficit you try to create. 

But what if you could override your body’s overriding?

It’s something you could totally do, by the way, according to a 2023 meta-analysis published in Advances in Nutrition.

After analyzing how well several different fat loss protocols worked for fat loss, the researchers found 2 things:

1. Cardio alone was the least effective fat-loss method, only ranking ahead of “no intervention”
2. The more dietary + exercise changes stacked with cardio, the better the fat loss results

The first finding is unsurprising. 

So, let’s talk about the second: what are these supposed “dietary + exercise changes”? Look at the top 4 effective fat loss methods; in order of decreasing effectiveness, they are:

1. Energy restriction + high protein + exercise (most effective)
2. Energy restriction + resistance training
3. Energy restriction + mixed exercise
4. Energy restriction + aerobic training (less effective)

Hmm. But why would adding any of the factors above lead to better fat loss results than cardio alone? Answer: they override your body’s attempts to keep your energy balance status quo. More specifically:

Don’t just rely on cardio for weight loss

All that to say, it’s likely you wouldn’t see the weight loss results you’re looking for without doing at least 1 of the following:

• Energy restriction
• A high protein intake 
• Resistance training

*shocked face* Uh, doing? Not adding to cardio? 

Yes, the truth is that you don’t even need cardio to lose weight. 

The proof is in the 2023 meta-analysis, which ranked energy restriction + resistance training (no cardio!) as the second most effective fat loss protocol.

But this doesn’t mean “Don’t do cardio at all!”

Instead, there are still 2 compelling reasons you should do cardio:

1. Cardiovascular health: Research suggests that combination training (cardio + resistance training) provides more comprehensive benefits on cardiovascular disease risk factors than time-matched cardio or resistance training alone.
2. Burns more calories than strength training: Resistance training burns very few calories compared to cardio in the same amount of time (3.5 METs vs 8.3 METs seen with running at 8 km per hour, for example). In that sense, cardio could make creating a calorie deficit “easier” for you (e.g., you wouldn’t need to resort to a very low-calorie diet) — provided you consciously restrict your calorie intake, of course. 

And this begs the question … 

How much cardio should you do?

Back to the OG question: how much cardio should you do for weight loss? And cardiovascular health benefits? 

TBH, this might seem … anti-climatic after everything we’ve been through, but a good rule of thumb is sticking to the CDC’s recommendation of:

• 150 minutes of moderate aerobic activity weekly or
• 75 minutes of vigorous aerobic activity weekly

FYI, during moderate aerobic activity, you can talk but not sing. On the other hand, you’re not able to talk or sing during vigorous aerobic activity. 

Finally, a reminder before ending this article: cardio type does not matter for fat loss.

We’ve established that at the very beginning. 

So, this means you’re free to choose a cardio activity that you best enjoy — be it running, cycling, hiking, rowing, or [insert your choice], just make sure it’s something you’ll likely stick to in the long run. 

Because consistency is ultimately what matters most for weight loss.