7 reasons why you gained weight overnight

Stepped on the scales today and your weight is up? IT’S NORMAL! Everyday your scale weight will fluctuate due to a HUGE variety of reasons! Just because your weight is up overnight, doesn’t mean you have gained fat!

Weight fluctuations are temporary and can often be explained. They have absolutely nothing to do with your long term progress! Here are 7 common reasons why your weight has increased overnight that have nothing to do with fat gain:

1. You ate more sodium than usual

If you consume more sodium than your body is used to, you will likely retain water the following day.

2. You ate more food than usual

The food we eat every day weighs something! Eating a larger volume of food in a day can result in an increase in weight the following day. Eating later than usual can affect your weight the following day.

3. You ate more carbs than usual

For every gram of carb you consume, your body retains about 2.7g grams of water. If you eat more carbs than usual on a particular day, you’ll often find that your weight is higher the following day. This does NOT mean you should avoid carbs!

4. Where you are in your menstrual cycle

It’s normal to gain 1-3kg of fluid around the time of menstruation, which usually peaks on the first day of your period. Many women also find that they retain fluid around the time of ovulation.

5. Your toilet habits aren’t regular

As your body processes food, it produces waste. Until you eliminate that waste, it’s carried inside of your body, and it factors into the number on the scale. If you aren’t eliminating waste regularly, your weight will often increase.

6. You had a hard training session

Lifting weights causes micro-trauma to the muscle tissue. In order to rebuild the muscle fibres to make them stronger, your muscles retain water to speed up the process in the cells. A similar response occurs with injury or other causes of inflammation.

7. You’re under a lot of stress

Periods of high stress causes the release of cortisol (stress hormone) which can result in fluid retention. This is true for any type of stress on the body – physical or emotional.


With weight fluctuations, you’ll often find that your weight will normalise within a few days. The worst thing you can do is start killing yourself with cardio or extra training and slashing your calories to try and get the number down – just stick to your normal diet and training routine!

It’s also important to remember that the scales alone cannot measure changes in body composition! That’s why it’s better to use a variety of tools to measure progress such as girth measurements and photos!

If you’re looking for a sustainable, science-based approach to achieve your goals – check out our 1:1 Personalised Coaching!