Here’s How Working Out Can Actually Make You Gain Weight (And What To Do About It)

Here’s How Working Out Can Actually Make You Gain Weight (And What To Do About It)

The harder you work out….the more weight you gain? What?

The point of this post isn’t to discourage you from being active, so please don’t go there. Exercise is hugely important for health and wellbeing, and seriously – I have zero idea how I would manage my stress without activity. I don’t even want to think about it. Exercising too much, however, can actually increase your weight. If you’re trying to lose weight, this can be pretty discouraging. I’ve been there!

A long time ago, in my twenties, I ran a marathon. I ran a lot in those days, because I was young and my job allowed it and I lived in California – I had perfect running weather all year round. I know, so jealous right now as I sit here in Toronto on the cusp of winter. 

I ran a lot to keep my weight down, too. I figured that running 26.2 miles, and all of the training leading up to the race, would definitely lean me out. I mean, three-hour training runs burn a lot of calories, right? 

So imagine my surprise when I actually gained weight while training for my first marathon. Whoa. 

Now that I’m older and wiser, I know that weight gain with intense exercise is actually a thing. Yup…the more exercise you do, NOT the better. Even though it might be tempting to work out like crazy if you want to lose a bit of weight (paging all those ladies who pull double classes at my gym), it can actually be counter-productive.

We already know that tweaking your diet, not just exercising until you drop, is a far better way to lose and maintain a healthy weight, but for all of you who are exercising up a storm and aren’t seeing any gains (or losses), you might want to rethink your routine.

Here Why You Gain Weight While Working Out

Compensatory behaviour.

We all have compensatory mechanisms built right into our bodies, to help ensure that our weight doesn’t go below a certain level. You can probably blame the food scarcity in the caveman days for those genetics. 

These compensatory mechanisms work really efficiently to keep us at the same weight. They work like this: 

We pull that double spin class, then become hungrier due to all of the effort. Your body recognizes that you’ve burned a few too many calories, and your hormones respond by increasing hunger to that point where you can’t ignore it. You’re more likely to overeat, because those hormones – and hunger pangs – can be relentless. 

Those hours of exercise also mean that we’re sort of tired afterwards, leading us to move less overall (AKA I worked out! now I can sit on the couch!). We compensate, therefore, for the extra activity by sitting more. 

As if that’s not bad enough, all the stress of overexercising can cause cortisol levels to rise, making it even harder to lose fat. GRRRR!

Isn’t science grand?

To avoid this, find a workout regimen that works, but stop killing yourself with the double workouts and crazy tough routines. As with most things in life, more isn’t better, y’all!

Also, be aware that you’ll need to continue to move throughout the day – your workout doesn’t get you out of having to do other activity. 

Permissiveness, AKA: I exercised, therefore I drink/brunch/eat three donuts.

When I was training for that marathon, I swear I was like an eating machine. I was starving (see point #1), but I also figured that I was burning off everything I ate anyhow. 


I was working in a hospital at the time (I had just graduated from nutrition), and I distinctly remember being in the ICU seeing patients and noticing a box of donuts in the break room. I frigging attacked those donuts (Aside: American apple fritters are the best) and ate three (including said apple fritter). I did this often, with all sorts of food. I earned it, so I ate it. Except no.

Behaviour like this is how I gained weight during that time, and I ran that marathon with five extra pounds. Believe me when I tell you that I felt every ounce during those four hours.

We already know that we can’t exercise off a bad diet, and that working out in order to eat more isn’t an effective practice. Diet is the main factor in weight, so it’s better to consider your workout as an ‘extra’ – not the reason to eat more.

Overestimating calorie burn.

This one goes hand-in-hand with permissiveness. 

Research actually suggests that we overestimate the calories we burn during exercise, leading us to believe that we can ‘afford’ to eat more on those days. The truth is that we burn a heck of a lot less during exercise than we think, and those ‘counters’ on devices tend to poorly estimate calories expended. Don’t be fooled. In fact, we only burn off between 10% and 30% of our calories with intentional exercise (versus activities of daily living, thermic effect of food, and basal metabolic rate). That’s not a heck of a lot if you’re indulging often and in large quantities. 

Again, my suggestion is to not treat exercise as a way to ‘cover’ your dietary indiscretions. In other words, exercise for health, not for weight loss. 

You can’t burn off a crappy diet. 

Overcompensating for overeating.

Who hasn’t tried to overexercise to ‘burn off’ a few extra calories from a meal (or meals) that they’ve eaten? We’ve all done it, but many times, it ends up being a downward vortex of overeating – overexercising – overeating – overexercising. AHHHHH! SO EXHAUSTING! STOP!

Break the cycle by first understanding that what’s done is done, and that a crappy day or week probably won’t affect your weight if you simply go back to eating normally as soon as you can. That’s right – it’s fine to exercise after indulging, but try not to freak out and go all savage-like in order to burn shit off. My post on how to get back on track after overeating can offer more guidance if you need it!


It’s all about balance. For me, I’ve learned my ‘sweet spot’ for exercise frequency and duration where I reap the benefits without overdoing it. All you need to do is find yours.