Why Am I Working Out But Gaining Weight?


Many people start working out to burn more calories and lose weight. Many of those same people soon find themselves in a curious position: they are working about, but gaining weight. If you are one of these people, you might be wondering, “What in the world is happening?”

In this article, we’ll discuss reasons for weight gain even when you’re working out, as well as how to manage it. While it’s definitely frustrating that you’ve been working out but not hitting your weight goals, it’s important to keep it up. You will start to lose that weight!

Reasons Why You Might Be Gaining Weight After Exercise

There are a variety of reasons you might be gaining weight even after exercising, so you’ll have to pinpoint which one is most likely for you.

Water Weight

About 75% of our bodies is water. That’s a large portion of our weight. And the amount of water in our bodies fluctuates regularly. This means that there can be significant amounts of variation on the scale depending on how much water we have in our body at the time.

Sometimes after working out, there can be water retention. When you step on the scale, the number will be higher, but your body composition hasn’t changed in any way. Give it a couple of hours and you’ll likely see a lower number.

If you want to retain less water after your workouts, make sure that you’re staying hydrated. It seems counter-intuitive, but then your body knows that it doesn’t have to store up as much extra water.

Muscle Mass

Another reason you might see what appears to be weight gain is if you’re increasing your muscle mass. It’s not quite accurate to think that muscle is heavier than fat. It’s just that the volume of muscle is denser and therefore heavier.

Muscle mass will change your body composition. You’ll be getting more muscle mass and decreasing the amount of body fat, so the scale may not be super helpful to you for a while since it won’t accurately portray this change. Adding muscle while losing fat can make weight fluctuate.

Developing lean muscle is key to healthy weight loss, since muscle burns more calories that fat does, even when you are at rest. If you have gained weight because you are putting on muscle, this should be seen as a positive. We’re aiming for healthier bodies, after all – not simply lower weight.

Temporary Weight Gain

Challenging workouts can cause temporary weight gain. The stress on your body can cause weight gain as your body adjusts. This may even be an indication that you’re working out too much and/or too hard and that you need to tone it down.

When inflammation occurs in damaged tissues, this can manifest itself as weight gain, but it’s only temporary. You’re a more likely candidate for this type of weight gain if you’ve been pushing hard and dealing with delayed-onset muscle soreness the day or two after your workouts.

Poor/Unhealthy Diet

It is easy to find runners online who seem to celebrate each run with a cheeseburger, fries, and a beer. “Calories need to be replaced!” they say. Calories do, in fact, need to be replaced, but making healthy choices will give your more success in managing your weight. 

Keep in mind too that most fitness trackers, such as Garmin, Strava, and Fitbit, are known to overestimate the number of calories you’ve burned. People are also known to underestimate the calories they consume. This is a dangerous combination, especially once you get post-run cheeseburgers and beers involved.

Exercise alone isn’t enough to lose weight. You also need a healthy diet. Make sure that you’re getting plenty of fruits and vegetables, including leafy greens, going easy on red meat, avoiding saturated and trans fats, skipping excessive salt and added sugars, and eating whole grains and low-fat dairy products.

Marathon Training

Although this seems extremely counter-intuitive, it’s not uncommon for runners to gain weight when they start training for a marathon. More miles give runners a sense that they can eat whatever they want. However, you still need to be mindful of food after long runs.

Think about it this way. Let’s say that you go for a 15-mile run and burn 1,500 calories. There’s a good chance you’ll want to celebrate after to mark your successful completion of such a long distance.

You’re not going to go to a salad shop. You’re going to get wings, pizza, or some sort of junk food that is wicked high in calories. It’s great to burn so many calories running such a long distance, but you won’t lose weight if you’re inputting more calories than you’re burning.

How To Manage Weight Gain After Exercise

Although you might feel really frustrated right now because you just want to lose weight, just take a few deep breaths and tell yourself that it’s going to be okay. Because it is. Pressuring yourself will just make things worse. 

Weigh Yourself Less Frequently

While it might seem like weighing yourself every single day is the best way to track weight loss/gain, it’s just going to make you uptight, speaking from experience. You’re better off weighing yourself less frequently.

This will give you a better sense of weight loss/gain over time. I’d recommend doing it at a scheduled time so that you aren’t tempted to sneak in a weigh-in. Maybe the 1st of every month or every time that you get paid, as a way to remember.

You also might want to put your scale away if you have it out so that it’s less tempting to weigh yourself. One of my friends who got a little too obsessive about weight loss threw her scale away because it was making her stress out about something she loved—running. 

And always keep in mind that your weight always fluctuates day-to-day. No one is the same weight every day, and no one who is losing weight loses weight every consecutive day. For a variety of reasons, you’ll weigh a pound or two more (or less) on a regular basis. If you are tracking your weight loss, look at long-term patterns, not daily fluctuations.

Stick With It

You might feel like you want to throw in the towel, saying to yourself, “I decided to start exercising to lose weight, and I can’t even do that.” But before you go condemning yourself, just give it some more time.

Register for a race that is a couple of months away and seriously train for it. Don’t weigh yourself until the day of that race. And then see how you feel and how much you weigh a few months in the future. Chances are that you’ll have lost some weight and feel great.

Remember that if you’ve experienced weight gain after just beginning to exercise, it’s probably temporary. Continuing with exercise will offer long-term benefits beyond weight loss. As we all know, exercise helps with mood, sleep, and overall physical health.

If you want to be going strong into your 80s and 90s, you have to be out there exercising when you’re in your 40s and 50s (or even younger). Exercising is also a great way to get outside and get some vitamin D, and it’s a great confidence booster. 

While weight loss is a great reason to start exercising, I think you’ll find that if you stick with it, weight loss won’t be the reason that you continue exercising. 

I personally exercise because I get to enjoy nature, remind myself how lucky I am to be able to run, and get some time alone with myself. It’s a peaceful part of my day that allows me to get away from all my worries. Getting in great shape is also a nice side benefit!

Focus on Healthy Habits

Time management expert Laura Vanderkam recommends process goals over outcome goals because they typically achieve better results. Plus, they are easier to stick with. So instead of telling yourself you’re going to lose 20 pounds, tell yourself that you’re going to exercise 3 days a week.

By exercising 3 days a week, you’ll definitely start to lose weight. It’s so much less pressure on yourself. Plus, you’re getting yourself into a healthy routine that you can hopefully keep up and sustain.

Eat Right and Drink Enough Water

Don’t think of a number. Rather focus on healthy habits. This means staying hydrated and eating healthy foods. If you’re not sure if you’re drinking enough water, check your urine. It should be a very light yellow. If not, start drinking more.

There are many ways to eat healthy, but central to almost all of them is to start with fresh ingredients. Processed foods, frozen foods, and foods with value-added nutritional claims should be eaten sparingly.

Get Plenty of Sleep

Make sure that you’re getting plenty of sleep. Our bodies desperately need 7-9 hours to function properly. You’re affecting your family life, work life, and personal life by not getting the rest that you need.

Take Time to Recover

You’ll also want to ensure that you are getting enough recovery. While hard workouts are key to fitness and weight management, you can’t do it every day. Make sure that you schedule rest days. You might even want to select one day that you always take off, like Sundays.

Manage Stress

Finally, you’ll want to understand and manage stress. No matter what your exercise goals, good mental health should be a part of them. That means that you have to get your stress under control. Be aware of stressful things and try to come up with healthy solutions.

If you’re super stressed, your body will likely tell you to eat more to replenish food supplies, which is the last thing that you want if you’re trying to lose weight.

Final Thoughts

In the end, focus on getting more fit, not necessarily losing weight. While it’s great to shed the pounds and tone your body, if you’re a little heavier now because there’s more muscle, that’s a good thing.

And just because you’re slimmer doesn’t necessarily mean that you’re healthier. Having a well-rounded approach that focuses on a healthy diet, good sleep, and successful workouts is the best way to approach your new exercise routine.