Why You Won’t Lose Weight With Cardio Alone
We can all do some form of exercise and be more active, whether it is running, weightlifting, hiking, cycling, rowing or whatever gets you out of your chair to break a sweat. We need exercise as a way to enhance health.
However, adding an exercise routine to your life without making nutritional changes will not get you where you want to be, or even nowhere. To be completely honest, you can can even make things much worse. Exercising without fuelling yourself with the right food and nutrients will just put an extra strain on your body and central nervous system.
We know that fat loss simply comes down to burning more calories than you consume. So, it only makes sense that if you want to lose weight, you need to exercise more. But cardio alone isn’t nearly as effective for fat loss as you might think. The main purpose of this post is to explain you why you won’t lose weight with cardio alone.
Top reasons why cardio alone is not enough for weight & fat loss
Now that we’ve established that exercise isn’t as useful for weight loss as you might have been led to believe, we’ll briefly explain the science behind why this is the case.
Let’s use some simple math to compare diet and exercise.
#1 Exercise doesn’t burn that many calories
Unfortunately, exercise doesn’t burn as many calories as we’d like it to. When people do exercise, they often overestimate how many calories they burn by 3 to 4 times. This leads them to believe that they’ve earned the right to sweets and treats post-workout. But it doesn’t take much food to eliminate all the hard work they’ve done. As a result, most studies find that exercise alone leads to little or no weight loss.
With diet, it’s relatively easy to reduce your consumption by 500 calories per day. A few simple changes, such as cutting out sugary foods and drinks, could be enough to do the trick. With exercise, it’s very difficult to burn an additional 500 calories per day. You would likely have to do cardio for 45 minutes, 7 days a week. Not exactly an easy or sustainable fat-loss strategy.
Therefore, it’s much easier to resist a small 250-calorie pack of Skittles (they’re vegan), than to burn 250 calories on a treadmill. Unless you’re doing triathlon training, exercise will probably only burn around 10 per cent of your energy intake per day. When you consider that your appetite increases and that exercise makes you crave high-calorie foods, it’s even harder to achieve any significant calorie deficit.

#2 Wrong attitude: You’re using cardiovascular training to overcome bad eating habits
“Oh, right after this meal, I’m going for a run” is one of the things you may have heard or may even have said as you stuffed down the last crumbs of cheesecake from the buffet table.
There are many people out there who think that it is OK to eat a packet of biscuits, a big piece of cake or big slab of unhealthy chocolate because they will go for a run straight afterwards. This is no way to lose weight and achieve the results you want. In fact, you’re putting in all that effort for nothing.
While we enjoy a good meal just like any of you, it is important to understand that it is next to impossible to out-train bad food habits.
If you feel like eating a piece of cake or a vegan biscuit, go ahead and have one. That’s normal and OK, on the odd occasion. But don’t get into the habit of eating badly and thinking you can exercise it off. It simply doesn’t work and will leave you feeling dejected and upset at the lack of positive results. Wrong attitude is the biggest reason why you won’t lose weight with cardio alone.
#3 It is next to impossible to out-train bad food habits
Why? Even a hard training session uses about six-hundred calories per hour.
However, that is just one Big Mac worth of food. Add fries and a soft drink and you are up to more than one-thousand calories. Can you run more than 90 minutes? While we’re not a big fan of calorie counting as a lifestyle, it should be pretty clear that it is impossible to eat “whatever I want” and get great results.
The only exceptions to this reality are those who are genetically very adaptable to eating a lot – naturally skinny people.
#4 You’re underestimating your calorie intake
People generally overestimate how many calories they’ve burnt, while underestimating how much they eat.
#5 You’re overestimating your calorie consumption
You burn only about 400 to 500 calories running for an hour (depending on how fast you run in that hour). A Domino’s pizza has around 370 calories per slice – and when do we ever just eat one slice of pizza?
#6 Our bodies adapt
The human body is highly intelligent. When you exercise a lot and often, your body becomes more efficient at storing calories, and you end up burning fewer of them. This is known as “metabolic compensation”.
#7 Exercise can increase cortisol and promote fat storage
Although exercise does increase metabolism, when you push yourself too much it can have the opposite effect and prevent weight loss. Pushing ourselves to do long runs, for example, can cause the body to release the stress hormone cortisol to keep us going, yet this hormone also encourages fat storage around the middle. One more reason why you won’t lose weight with cardio alone.
#8 We can begin to resent exercises
As we’ve witnessed firsthand through many clients, when you think you need to exercise to lose weight and you don’t see the number on the scales dropping, you become resentful and begin to resent exercise. This can sabotage your relationship with physical activity, which should be something enjoyable and part of maintaining good health, not viewed as a chore and a punishment carried out solely in a misguided attempt to lose weight.
#9 Increased appetite
Although you might not feel hungry immediately after a workout, you’ll definitely notice that on the days you’ve exercised your appetite increases later in the day. If you’ve ever been swimming or had an intense morning workout, you’ll probably have noticed that you get ravenous later in the day. Often, you end up eating more calories on those days than you actually burnt off, because your hunger is so much greater. On top of increased appetite, exercising makes your body crave high-calorie foods to replace the lost energy from intense workouts, making it that much more difficult to resist a post-workout binge.
Which type of cardio workout should we choose?
The two most commonly cited excuses for why people don’t do cardio is a “lack of time” and a “lack of enjoyment. So, it’s only sensible that we look for alternatives to traditional endurance exercise (traditional or low intensity steady state cardio)—where you exercise at a steady pace for about 30-60 minutes.
Another type of cardio that is increasingly popular is high-intensity interval training (HIIT). With HIIT, instead of exercising at a moderate-intensity for a long time, you exercise at a high intensity for a short time. For many of us, the challenge of all-out sprinting and the variation in intensity is more enjoyable than the monotony of jogging on a treadmill for 30-60 minutes. There are also many other benefits of HIIT training.
Summing up: Why You Won’t Lose Weight With Cardio Alone?
You simply can’t outrun a bad diet.
Relying on exercise for weight loss is a major mistake that many people make because they’ve been led to believe that it plays a big part in achieving great results. Whereas keeping active definitely plays a part in a sustainable weight-loss regime, it is certainly not the major part of it. You can exercise all you like, but if you are eating a bad diet full of unhealthy fats, sugar and processed foods you are unlikely to see any results. The key to weight loss is what goes in your mouth. As any personal trainer will tell you: “Abs are made in the kitchen”, and “You can’t out-train a bad diet.”
Losing weight is truly 80% diet and 20% exercise. You should always view your diet as the foundation that ensures fat loss and cardio as what accelerates fat loss.