If you’ve ever wondered why cardio doesn’t work for weight loss – even when you’re doing a ton of it – you’re not alone. I hear this question all the time: “Why isn’t my cardio working?”

One reader told me she’d been doing cardio almost every day for weeks. Not only that, she had even increased the duration of her workouts. But the scale barely moved.

When that happens to you, that’s when frustration sets in. You start wondering what you’re doing wrong, or worse, what’s wrong with you.

The truth is, there’s more than one reason why cardio for weight loss doesn’t work the way people expect. In another article, I explain a major reason: you can’t out-train a bad diet. Differently stated – you’re eating back the calories you burned (oops!)

But there’s another, lesser-known reason behind this problem that I want to show you today, and it has to do with something called N.E.A.T.

Man on treadmill frustrated that cardio isn't working

Why Doing a Lot of Cardio Doesn’t Guarantee Weight Loss

Question: How is it possible that some people do tons of cardio and still don’t lose weight?

Answer: Because weight loss is a function of a calorie deficit, not how much cardio you do.

Cardio is just one tool you can use to help create that deficit. It’s not a guarantee.

Endurance athletes are a perfect example of the error in thinking that “an hour a day” (or whatever amount) of cardio will make you lose weight.

They might train one, two, or even three hours a day – yet many of them aren’t trying to lose weight at all. In fact, they have to eat huge amounts of food just to fuel their training and keep their weight stable.

It’s not unusual for a cyclist to burn 4,000 or even 5,000 calories per day and still maintain their weight.

With all that cardio, why doesn’t the weight come off?

For the same reason you might be doing a lot of cardio and not losing weight: There’s no calorie deficit.

Calories coming in are simply matching calories going out.

That’s why it’s a mistake to focus on hitting some magic amount of cardio time. The real prerequisite for weight loss isn’t hours on the treadmill – it’s a sustained calorie deficit.

If your calorie intake stays exactly the same and you add cardio or other activity, you will create a deficit and you will lose weight. That part is simple.

But here’s where most people get tripped up…

When we talk about cardio and training, we often forget about all the activity that happens the rest of the day – outside the gym.

That activity has a name: Non-Exercise Activity Thermogenesis, or NEAT.

Non-Exercise Activity Thermogenesis, or NEAT

NEAT is all your physical activity throughout the day, not counting your “formal” workouts.

NEAT includes all the calories you burn from casual walking, shopping, yard work, housework, standing, pacing and even little things like talking, chewing, changing posture, maintaining posture and fidgeting. Walking contributes to the majority of NEAT.

It seems like a bunch of little stuff – and it is – which is why most people completely ignore it. Big mistake! At the end of the day, week, month and year, all the little stuff adds up.

For most people, NEAT accounts for about 30% of physical activity calories spent daily, but NEAT can run as low 15% in sedentary individuals and as high as 50% in extremely active individuals.

I’m always telling people to exercise more – to burn more, not just eat less. This is not only for health, fitness and well-being, but also to help increase fat loss.

Some people say that increasing exercise doesn’t always work for weight loss and they quote from research to make their case.  It’s true that some studies paradoxically don’t show better weight loss by adding exercise on top of diet.

Why Adding More Cardio For Weight Loss Often Doesn’t Work

If you add training into your fat loss regime but you don’t maintain your diet discipline and keep your food intake the same, you remain in energy balance.

If a study doesn’t monitor this type of compensation, or if the researchers trust the subjects to accurately self-report their own food intake (hahahahahaha!), it will look like the exercise was for nothing.

In studies where the food intake was controlled when exercise was added… surprise, surprise, weight loss increased!

Stated differently, all these “experts” who keep saying that exercise doesn’t work for weight loss are  ignoring or not accounting for the concepts of calorie deficit, energy compensation, or both.

Why Exercise “Doesn’t Work” for Weight Loss – A NEAT Explanation

So a handful of people exercise and then eat more than they were eating before and then scratch their heads and wonder why they aren’t losing. Duh!

Or, they go on some idiotic crusade against exercise, usually while simultaneously promoting their latest diet fad. “See!” they proclaim, “Exercise is a waste of time! All you have to do is avoid these 3 evil foods and eat these 3 magic foods!”

Wrong. Dieting alone is not a good idea, because without resistance training, even if you lose weight, a higher percentage of the weight loss comes from muscle, which is hoe people end up “skinny fat.”

And without cardio training, you won’t be fit (picture the person huffing and puffing just going up a flight of stairs). You won’t be healthy either. Being sedentary is terrible for your health.

Want to lose weight, be healthy, and avoid skinny fat syndrome? If so, the prescription is nutrition, then weight training, then add in and manipulate the cardio as your results dictate. That’s the order of priority.

There’s another type of calorie compensation that researchers have recently been studying…

When people increase their training, especially high intensity training, sometimes they also compensate by moving less later in the day and even in the days that that follow.

For example, you work out like an animal in the morning, but then instead of your usual walking around and doing housework the rest of the day, you crash and plop your tired body in your Lazy Boy for a nice nap and a marathon session of Netflix.

The next day, the delayed onset muscle soreness (DOMS) sets in and then you really don’t feel like moving!

Research on NEAT is extensive. It tells us that NEAT plays a major role in obesity and fat loss. Finding ways to increase NEAT combined with formal exercise can be a great strategy to increase your total daily calorie burn and thus, increase fat loss.

The flip side of that equation is finding ways to avoid decreases in NEAT that we might not have noticed. Because NEAT is so completely off most people’s radars, most people miss this.

NOTE: For a real eye-opener, try a using a step tracker every day for a while.

Previous studies confirmed that many people compensated and decreased their activity (NEAT) during the remainder of the day or on rest days after formal training sessions. This led anti-exercise pundits once again to spit out their party line, “See, exercise doesn’t work! You might as well just diet.”

However, a study published in Medicine and Science in Sports and Exercise found no negative effect on NEAT on the day of exercise or on the following 2 days.

In fact, there was a delayed reaction and NEAT actually increased 48 hours after the exercise session (60 minutes of treadmill walking at 6 kph @ 10% grade with 5 minute intervals at 0% grade).

Why the conflicting findings? Scientists aren’t 100% sure yet, but they have discovered that part of it has to do with exercise intensity.

Moderate vs High-Intensity Cardio: Effect On NEAT

You sometimes hear certain trainers claim that only high-intensity exercise is worthwhile and everything else is a waste of time or at best inefficient. That’s not always true, on many levels, and one of them involves NEAT.

It looks like higher intensity training has more potential to decrease NEAT later on than low or moderate intensity training.

You burn a lot of calories during the workout when you train with high intensity. However, the calories burned during the formal training can be at least partly canceled out by a decrease in NEAT outside the training session.

Differently stated, high-intensity training really tires you out, and the fatigue can linger.

It also appears that moderate intensity exercise may be better tolerated than high intensity exercise by some people, especially beginners and the obese.

The low or moderate intensity workouts don’t wipe them out so much, so they don’t become fatigued, sluggish and sore later in the day…. and there’s no drop in NEAT.

Am I Saying You Shouldn’t Do High Intensity Exercise? Not At All

High-intensity training can be very effective and time efficient, and a mix of high and lower-intensity training might be ideal.

But if you do a lot of high-intensity work, you have to be aware of how OVER-doing it might affect your energy and activity level outside the gym – on the day of training, and even in the days that follow the intense workout. Otherwise, you might end up with fewer total calories burned at the end of the week, not more.

If you don’t understand the calorie balance equation and the calorie deficit, and if you don’t understand the compensatory effect of NEAT on energy out, and the effect of eating behaviors on energy in, then you can do cardio until you’re blue in the face and you’ll still be in energy balance… and your body fat will stay exactly the same.

If you control your diet and if you can keep your NEAT levels up, then cardio of all levels of intensity can help with your weight loss – lower intensity exercise like walking, moderate intensity steady state training and also high intensity interval training.

Using a fitness tracker with a pedometer to count your steps can be one of the BEST ways to make sure you keep your NEAT up.

At Burn the Fat, we try to help you with this mission by sponsoring walking challenges throughout the year. These events give you motivation and the social connections and accountability that a fitness tracker device alone may not give you. You can learn more here. 

Important Points (30-Second Summary):

1. The study I mentioned in this blog supports the role of exercise for weight loss and debunks the idea that exercise doesn’t work for weight loss, provided all else remains equal when exercise is added on top of diet.

2. Exercise intensity can affect NEAT for days after a workout is over. Too much high-intensity work might zap your energy and activity outside the gym, resulting in a lower level of NEAT. You have to keep up your habitual activity level outside the gym after pushing yourself hard in the gym.

3. This information supports the role of low to moderate intensity exercise (like 40-60 minutes of treadmill walking) based on the effect this has on your activity outside the gym. It is not true that only high intensity training is worthwhile. There are pros and cons of training at various intensities. Not zapping your NEAT is one of the pros of lower intensity exercise.

4. If you can keep up your NEAT while you add formal cardio, you can increase your weekly calorie expenditure and increase your fat loss.

5. Before you take any research at face value, it’s important to look beyond short-term results (during a single workout or a study that only lasts 24 hours, etc), and also consider longer term effects. We should all keep our eyes out for studies that go beyond 24 hours to get some idea of the long-term impact exercise is really having.

Post in the comments below if this finally clears up the ‘exercise doesn’t work for weight loss’ nonsense. I’d love to hear what you think.

Tom Venuto,
Founder, Burn the Fat Inner Circle
Author, Burn the Fat, Feed the Muscle
Author, Flexible Meal Planning For Fat Loss

PS. Another major reason cardio “doesn’t work for weight loss” is because you out-eat your exercise – you exercise but then put all the calories you burned right back. Read more here: Why you can’t out-train a bad diet

PPS. Some people think cardio doesn’t work for weight loss because your body (metabolism) adapts to the cardio and you stop burning as many calories.  A major study suggested that. There’s a sliver of truth here, but it’s highly overblown. Trust me – as long as you don’t out-eat your exercise, increasing your cardio will burn more fat. Learn more:  Does calorie compensation cancel your cardio?

Scientific reference:
Exercise Intensity Influences nonexercise activity thermogenesis in overweight and obese adults. Alahmadi MA et al, Medicine And Science In Sports And Exercise, 43(4): 624-631.


tomvenuto-blogAbout Tom Venuto
Tom Venuto is a natural bodybuilding and fat loss coach with over 35 years of experience. He holds a degree in exercise science and has trained hundreds of clients in person. He is also a recipe creator specializing in fat-burning, muscle-building cooking.

A former competitive bodybuilder, Tom is now a full-time evidence-based fitness writer, blogger, and author. His classic book Burn the Fat, Feed the Muscle is an international bestseller, first as an ebook and later as a hardcover and audiobook. His newest book. Extreme Fat Loss, which analyzes controversial diet and training programs, became an instant bestseller in 2025.

Tom’s work has been featured in Men’s Fitness, Oprah Magazine and dozens of other major publications. He is best known for his no-BS, evidence based approach to natural fat loss and muscle-building.

Tom is also the founder of Burn the Fat Inner Circle, a fitness support community with more than 53,000 members worldwide since 2006.


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