Exercise is one of the best things you can do to stay fit and healthy. In fact, it’s impossible to be healthy without some physical activity every day. If you don’t move your body for a long time, your muscles start to shrink and lose their function. But can you lose weight with just exercise? 

If you are planning to lose weight, you might be wondering if you can do it just by hitting the treadmill, cycling to work, and generally getting enough exercise.

The short answer is: you might, but it’s unlikely.

Researchers have explored this question extensively. And while it might be possible if you already eat right, sleep well, and have your hormones balanced, in most cases, sustainable weight loss happens when you approach it in a holistic way.

Here’s more about the challenges of losing weight by exercising alone and what you can do instead. 

woman lacing up her shoes outside to go for a run

Why is it hard to lose weight with just exercise?

We’ve all looked at athletes, dancers, sporty types or general gym lovers and wished we had their motivation….and their body composition. But the truth is that the old saying ‘you can’t outrun a bad diet’ holds true for most people.

Weight gain, maintenance, or loss is a result of the interplay of complex body processes which include food intake, energy expended in keeping your body working, physical activity (aka exercise), hormones, and even genetics. 

Attempting to lose weight by focusing on just one part of the process—in this case, exercise— is unlikely to give you the best results for several reasons.  

1. Plenty of exercise typically burns just a few calories

Exercise often feels like it’s burning a tremendous amount of fat and calories. After all, it’s A LOT of effort. When sweat is running down your face and you feel your heartbeat race, you’ll think you have burned a ton of pounds. It seems unfair you don’t immediately have a six pack after a killer gym session sometimes. 

But this is simply not the case. Losing weight through just exercise is hard because you don’t actually burn that much fat from a typical gym session. 

Studies show that it takes a huge amount of effort to burn calories from even small amounts of food. For instance, data from the Royal Society of Public Health estimates that it takes: 

  • 42 minutes of walking or 22 minutes of running to burn 229 calories– the amount in a standard chocolate bar.
  • 26 minutes of walking and 13 minutes of running to burn the 138 calories in a typical sugary soft drink.
  •  1hr 22 minutes of walking or 42 minutes running to burn the 449 calories in a quarter pizza. 

Sorry! That walk around the block definitely didn’t burn off an entire tub of ice cream, as much as we sometimes wish it did. 

It’s clear from this that if your diet is high in processed foods with added sugar and saturated fat, it can be difficult to burn all those calories through exercise alone. 

family exercising together playing soccer outside

2. Your body conserves energy when you exercise a lot 

Scientists noticed this phenonemon for the first time when comparing hunter-gathering communities to communities with sedentary lifestyles. They found that there wasn’t a great increase in the amount of energy burned each day in the hunter-gatherer societies. 

Subsequent studies showed that when your physical activity levels increase, your body adjusts by reducing the amount of energy it uses. This means that it will take much more energy expenditure through exercise to create any weight loss than a simple increase in physical activity.

3. As you lose weight, your body burns less calories

Early weight loss models calculated expected weight loss using the person’s current weight. But they found that the actual weight loss was less than they expected. This was because as you lose weight, your energy use also reduces. 

So, for instance, with 30 minutes of exercise, you could burn 150 calories at your initial weight As you weigh less, you will burn less than that even when you exercise for the same amount of time. And this doesn’t even factor in that as you get fitter, you have to work harder to raise your heartrate too. 

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4.Lots of exercise can increase your appetite 

Anyone that’s tried to increase their activity levels massively and suddenly has probably experienced this—raging hunger like never before. 

As you exercise more, your appetite is likely to increase because your body wants to replenish any lost stores of energy. 

If you aren’t prepared for this, it’s easy to overeat and refill or even exceed any calories lost from exercising.

5. Focusing on exercise can make it seem like punishment 

If you focus on exercise as the only way to lose weight, it can begin to seem like a punishment. When exercise has a negative feel, it becomes harder to stick to. Just like with food, it’s important to develop a healthy and lasting relationship with exercise.

While it can be a beneficial part of weight management, it should also be something you do because it makes you feel good. When you can’t stick to your exercise regime, you lose its benefits. Of course, this makes it easier for any lost weight to be regained. 

6.  Some people’s bodies are wired to lose more by exercising than others 

It’s clear that some people lose weight more easily than others. What isn’t so obvious is that some people are more likely to lose weight from exercising than others. 

Those people, known as ‘responders,” find it easier to lose weight by increasing their physical activity. 

But if you aren’t one of them, you may find that even after lots of exercise, your body doesn’t appear to lose any weight. 

Also, scientists have found that your body type (i.e. ectomorph, mesomorph or endomorph) can also influence your body’s responds to exercise. If you are an endomorph, losing weight from exercise is likely to be harder than it would be for other body types. 

middle aged woman in swimming cap checking her sports watch in pool

Why you still need to exercise 

If it sounds more and more like you should just stay in bed, don’t be fooled. Although exercise alone is unlikely to help you lose weight, you shouldn’t stop because it still offers plenty of benefits. Some of those benefits include:

  • Helps you maintain weight and prevents you from gaining more.
  • Builds your lean muscle mass 
  • Improves your mood
  • Improves your sleep 
  • Improves your heart health 
  • Reduces your risk of chronic disease 

And of course, when paired with a balanced diet, it provides a sustainable and healthy way to approach weight loss. 

Losing weight from exercise alone is no walk in the park. Pun intended! It takes a lot of time, effort, and focus. But despite that, the results are unlikely to be impressive. 

A more successful approach is to use a combination of changes in physical activity along with better diet, sleep, and other changes.