She has also had 16 wellness books published by major publishers including the bestselling Easy GI Diet, The Macro Method, Quit Alcohol (For a Month) and Eat 5. Her books have sold over one million copies.
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It’s frustrating to come home from your workout and look in the mirror to see a stomach puffed up like a balloon. What possible reason could there be for you to enter a gym with a (relatively) flat stomach yet emerge 60 minutes later, looking six months pregnant?
This happens to us all the time and so we wanted to know why it occurs.
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This post was first published in 2012 and republished in 2024 with extra tips and advice
The Common Culprit: Swallowed Air
Let’s face it; we’ve all taken a deep breath before diving into a set of squats or holding our breath trying to lift that extra weight. But did you know that once you let go, the extra-deep breath you take can trigger bloating.
Kesh Patel, a Research and Development Manager at Premier Training International, highlights that holding your breath during exertion can lead to larger-than-normal intakes of air and when taking in a gulp of air, some escapes into the stomach.
You can also swallow more air during high-intensity exercises, and this swallowed air also doesn’t just disappear; it can bloat your belly, making you feel like a walking balloon.
This air would typically escape as a burp, but while your body is otherwise engaged, it might get stuck, causing unwanted bloating.
Focusing on regular breathing can help minimise how much air you gulp down.
Hydration: A Sneaky Bloating Buddy
You need to drink while you exercise, as dehydration can reduce your ability to work hard. However, while trying to increase your fluid levels, you might also inadvertently swallow air alongside your water. Hello, gym bloat!
Ensure you stay well-hydrated. Sipping on water regularly rather than gulping down huge amounts at once can keep your belly feeling happy and flat.
Food and Timing: Bloat Triggers
You probably fuel up with carbs before your workout, but if you’re picking the healthiest, high-fibre carbs like whole grains, nuts, and seeds, they can also trigger bloating. Foods rich in fiber and resistant starch, such as beans and pulses, start fermenting in your gut, triggering bloating a couple of hours after consumption.
If you had a fiber-rich lunch just before your afternoon workout, your belly bloat might appear as your workout finishes.
Obviously, you don’t want to cut out your workout fuel, so if this sounds familiar, try using some of our gas-releasing tactics instead.
When Exercise Causes Weight Gain
While bloating is temporary, there are a few reasons why exercise might also cause longer-lasting inches around your middle the most common of which is that you might be accidentally eating back the calories you burned off.
Let’s do some number crunching: running burns around 600 calories per hour, but a large smoothie packed with calorific ingredients like nut butter or protein powders can easily cancel that out in about eight slurps. Mindful consumption is just as essential as your exercise plan for noticeable progress.
And you might find calories sneaking in for another reason too…
The Mind’s Sneaky Way: Moral Licensing
Moral licensing—an intriguing psychological twist where you reward your good behavior (exercising) with a ‘treat’ (extra fries). Unfortunately, such indulgences can counteract your fitness goals.
A good way to handle this is to use the Future You idea. This is where you imagine you’re the person you’re hoping to become with your workout (or other goals) and act like them now.
Stress – The Troublemaker in Disguise
Yes, stress! Exercise is a brilliant antidote to stress, but if you’re exercising to excess or going full out at every workout, especially if you’re stressed out in other areas of your life, it can actually raise cortisol levels. High cortisol loves your belly, adding extra cushion where you least desire it.
If you’re going through a high-stress period, listen to your body. Is your workout making you feel better afterwards, or are you tired, grumpy, or forcing yourself to do it?
If you are, you might want to do something more chilled for a day or two—that might mean yoga, but it could also mean walking outside or going for a swim.
When to Seek Expert Advice
If post-exercise bloating persists, check with a medical professional. Though usually harmless, bloating might hint at underlying health issues. Seek advice if you’re getting bloating regularly that doesn’t disperse or if it comes with other symptoms like abdominal pain, bowel changes or loss of appetite.
So, there you have it a number of reasons why your stomach might be bigger after working out. Do any of them sound like you?
Who is The Wellness Nerd?
My name is Helen Foster, and I’m a health journalist and wellness author. Publications I’ve written for include Women’s Health, Reader’s Digest, Body and Soul, Good Health at the Daily Mail, and more. I have also written 16 books on health and nutrition.
