9 reasons why you might have gained weight overnight

Laura Hampson
·4-min read
Gained weight overnight? Don't fret, it's completely normal. (Getty Images)
Gained weight overnight? Don't fret, it's completely normal. (Getty Images)

If you’re on a weight loss journey, the last thing you want to see when you step on the scales to see that you've gained weight overnight – especially if it’s a big increase.

Weight fluctuations are completely normal, which is why it’s often recommended to weigh yourself just once a week, or even once every two weeks as to not get fixated on a number.

However, the good news is that gaining weight seemingly overnight does not mean that your diet and gym routine is failing – but it can actually be caused by a plethora of different factors such as dehydration or even lack of sleep.

Health and fitness expert, Ashleigh Tosh at Goal Plans powered by MuscleFood.com, adds that eating later in the evening, an increased carbohydrates intake, and doing intense gym workouts can also lead to overnight ‘weight gain’.

"Our bodies are amazing machines and we have to look after and nurture them. Adding weight overnight really isn’t anything to be concerned about and certainly isn’t a reason to switch up your diet or fitness routine," she explains.

"It’s also not a reason to stop doing the things we all love. Eating out and increasing our carb intake can both cause overnight weight gain - but who doesn’t love a nice meal out and a bit of extra pasta or bread at dinner?"

Mid-section of young woman eating seafood pasta and having wine, sitting at an outdoor Italian restaurant during vacation. Luxury meal. Travelling for good food.
Eating a carb-heavy meal can see an increase in weight on the scales, but it will even out. (Getty Images)

Tosh adds that weight fluctuations are to be expected even if you are following a calorie controlled diet.

"Scales and weighing yourself is not the only way to check how you’re doing," she says. "What’s important is to take stock of how you feel and start taking other steps like measurements so you can see the changes to your body - even if the scales can’t."

So, what could be causing the overnight weight gain? Tosh outlines nine reasons below.

1. Doing an intense workout

Tosh says that, after an intense workout, your body needs time to recover from any small tears or stresses put on your muscles – which can lead to a little overnight weight gain. However, these workouts will be beneficial in the long run.

2. A poor night’s sleep

Sleep is an underrated part of any weight loss journey as it can be a key tool to appetite control.

"A good night’s sleep is important for your overall wellbeing," Tosh explains. "If you have a bad night’s sleep you may find you’re a little heavier in the morning due to water retention."

3. Dehydration

"If you don’t drink enough water, your kidneys start to conserve water and you gain water weight," Tosh says. "Start sipping again and everything will get back to normal. Staying well hydrated is a must for overall health and wellness."

Close up of a woman's hand filling a glass of filtered water right from the tap in the kitchen sink at home
Staying hydrated is important for weight loss. (Getty Images)

4. Having a meal out

Having a meal or drinks out can lead to overnight weight gain as alcohol dehydrates your body which makes it hold onto more water.

However, this shouldn’t stop you from socialising – at the end of the day it’s all about balance.

5. Digestion out of sync

Fibre, which is found in fruit, vegetables, and legumes, is an important nutrient for digestion as it can help to keep your bowel movements regular.

6. Eating later in the evening

"Eating later than normal can show up on the scales the next day - again, all perfectly normal," Tosh says.

7. Increase in carbs

"If you up your carbs - and who doesn’t every now and again - then you may feel bloated and gain weight overnight," Tosh explains. "As quickly as this happens, the weight will go again."

8. Your period is due

For women, their fluctuating hormones can dictate their weight, and Tosh says that pre-period weight gain is completely normal.

"Every woman is different - you may gain weight just before your period is due or on the first day," she adds.

9. Stress

"If you’re stressed, your body holds more water as it responds to the demands you’re putting on yourself," Tosh says. "This too is normal."

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