6 Reasons Running Isn’t Leading to Weight Loss

A woman running in the city

Whether we will admit it or not, part of the reason we all run is to keep the weight off. To stay healthy and live a long, happy life. Running is not always the most enjoyable form of exercise, but it is definitely effective, and besides, doesn’t that mean we get to enjoy a few more of those sweets without feeling guilty?

Today, we are going to look into the reasons why you might not be losing weight as quickly as you thought you would, or even gaining weight as you begin to run more.

By becoming more aware of what you are putting into your body, you can maintain your weight at a level you feel confident at, without restrictions. Running is hard, we know that, but we want to make it easy for you to reap the rewards, and make that hard work worthwhile.

Many runners will be thinking that their major goal is not to lose weight, but to perform on race day, and this should be the primary goal, but most runners cite maintenance of weight as one of the major reasons.

A man and a woman running outside while it's getting dark

You might be wondering: Is there anything I can do to speed up the weight loss?

Unfortunately, sometimes when runners first begin serious training, they end up gaining weight, which can be especially frustrating to new runners (and we wonder why so many runners do not keep it up!).

If you understand the science behind initial weight gain and the practical reasons why this happens, you can maintain a positive attitude toward your training. You can feel confident that those long-term improvements to both to your overall fitness and to your race times will come eventually.

Here are 6 reasons running might not lead to weight loss

1. The scale is a trickster

If the scale were a person, it would be considered a misleading trickster. A scale only provides one number, your absolute weight, which isn’t always an accurate measurement of what is happening in your body.

Drink a gallon of water and you are 8.3 lb (3.8 kg) heavier. 

These may be extreme examples, but it proves that your absolute weight on a scale is not necessarily a truthful assessment of changes in your weight, and especially your fitness.

2. Extra water storage 

When you increase your training to prepare for a goal race, your body begins to retain and store additional water to repair damaged muscle fibers and to deliver glycogen to the working muscles.

Likewise, you may even be drinking more water to stay hydrated after your runs. Water may add weight to the scale, but it is not accurate of the training adaptations.

3. Muscle weighs more than fat

We are not saying you are going to turn into a body builder within a few days of beginning your running program, but over time, your body will begin to build muscle and burn fat.

While this is great news for your overall fitness and race times, you’re actually gaining weight by replacing low-density fat tissue with high-density muscle tissue. While it may add a bit to the scale, it is a good change and will help you to continue to run faster and get fitter.

A man taking a short breaking during his run

4. Looking for short-term results

Did you know? It takes a deficit of 3500 calories to lose one pound (0.5 kg). If you want to lose weight safely and be healthy, you should aim for a 300-600 a day calorie deficit.

This will lead to losing 1-2 lb (0.5 – 0.9 kg) per week. Checking the scale every morning is going to reveal very little about your long-term progress or how much weight you have actually lost.

By getting in the habit of weighing yourself every day, you are monitoring the fluctuations in your hydration levels and other non-essential weight metrics.

In the same way you wouldn’t expect a 1 minute drop in your 5K PR after one week of training, after one week of running, you should not expect a 5 lb (2.3 kg) weight loss.

5. Eating too much to compensate

Here’s the deal: Running burns more calories than any other form of exercise, but while the energy demands of running are high, this does not mean that you can eat whatever you want and still lose weight.

Runners are guilty of justifying their unhealthy foods by saying, “I ran for an hour today, I earned it”.

Many running groups meet up at the local coffee shop after a weekend run. However, a Frappuccino and a small cake will quickly eliminate any caloric deficit from the run and actually prevent weight loss.

Running does burn a lot of calories, but you have to watch the amount of non-nutrient dense foods you consume, or you could quickly gain weight.

Likewise, as mentioned in the article on how to lose weight and still run well, you need to provide your muscles with the necessary carbohydrates and protein to recover. This is a delicate balance, and probably the most difficult element to losing weight while running.

A healthy lunch bowl on a wooden table

Recovery should be the focus, and your muscles receiving the nutrients they need to rebuild should be the priority. The harder you train, the more often you will get hungry and the real secret is to refuel with nutrient-dense and high quality foods.

Remember: Sacrificing recovery for a few less calories is not a good long-term plan. The numbers on the scale are arbitrary and focusing on them can be detrimental to your long-term progression. If you can continue to build your fitness and training levels, you’ll be running farther, faster, and be much healthier overall.


Runners will burn an average of 100 calories per mile, but this will change based on your pace, size and metabolism.

6. Hidden Calories

Sports drinks and energy gels are the best example of hidden calories, as they have a high caloric content.

It’s critical that you practice your fueling strategy during your long runs and hard workouts for optimal performance on race day. You also need to fuel your training and workouts to be able to complete long and arduous marathon workouts. Energy gels and sports drinks make this much easier.

However: This also means that the total number of calories you will burn from these long runs and hard workouts will be less than you think. But before you think about skipping them, remember, you need those extra calories for optimal performance and training progression.

Unfortunately, they can also be the reason you might not see the weight loss on a scale.

Conclusion: Focus on the right metrics

Here is what it comes down to: Running will not automatically result in an immediate weight loss.

Although running does burn more calories than any other form of exercise, the scale should not be the primary metric by which you gauge your fitness level and training progression.

Weight loss is always going to be an important part of why many people run, just don’t become a slave to the numbers on the scale.

Instead pay attention to how you feel – do you have more energy, feel stronger, and like the way your clothes are starting to fit? While not metric measurements, your emotions are a much more accurate measurement of your progression.


Tina Muir As a former elite runner, Tina knows what athletes need to focus on in their training. "I'm an expert at improving your running." View all posts by Tina Muir