There are only 2 things that can cause the scale to go up: fat and water. If your diet is on-point, then it’s not fat. Here are the 4 most common causes of weight gain from water retention and what you can do about it.
First, keep in mind that increased levels of water-weight don’t necessarily mean you’re not burning fat. (In other words, it’s possible for the scale to go up while you’re still burning fat; this article talks about that).
Second, the single most effective way to deal with water retention (as strange as it sounds) is to drink more water. The more water you pass through your system, the more likely your body is to realize that there’s no need to hold on to it.
So, what are the top four causes of water retention?
In this blog article, I talk about the effects of too much cardio and how more than about 5 to 7 hours of cardio per week can actually cause weight gain. The root-cause of this is that it causes your body to produce cortisol which not only blocks fat burn, but it also increases water retention.
In other words, high volumes of cardio can actually cause your body to gain weight rather than drop weight. Granted, any weight gains are just water (not fat), but it’s still demoralizing.
Excessive cardio isn’t the only cause of cortisol production. Anything that places your body into a state of unusual stress can also cause your body to produce the cortisol hormone which can, in turn, block fat burn and cause water-weight gain.
Not getting enough sleep, a high-stress job, or stress with family or friends can also trigger the same reaction.
Electrolyte Imbalance (Too much sodium or not enough potassium)
If you have a particularly sodium-heavy day, you’re almost always guaranteed an increase on the scale the next day. Sodium is an essential electrolyte; eating too much of it means your body requires large amounts of another electrolyte in order to balance it out.
So, what’s the electrolyte that balances out sodium? Potassium.
In fact, eating too much sodium (and not enough potassium) will cause you to gain water weight. But, even eating the right amount of sodium (if you have a shortage of potassium in your diet) will also cause you to retain water.
In other words, too much sodium and/or too little potassium can BOTH cause water retention.
Fortunately, because you log everything you eat, MyFitnessPal will tell you exactly how much potassium and sodium you’re getting with your food. Just open your daily meal log, scroll to the bottom, and hit the “Nutrition” button. Then flip to the “Nutrients” tab to see your potassium and sodium numbers in comparison to one another.
Aim for an ideal target of about 3:1 (3 times as much potassium as sodium). Or, if you eat 1,000 mg of sodium in a day, you should offset that with 3,000 mg of potassium to keep your electrolytes in balance and prevent water-weight-gain.
Note that this is mostly a psychological problem. Your body will self-regulate. Your potassium and sodium levels aren’t something you necessarily need to pay close attention to unless you’re REALLY trying to optimize the reading on the scale.
One warning about potassium: Taking too much of it at the same time can cause problems. Most potassium supplements can lead to complications even in fairly small dosages (99 mg in a single pill). Spread the potassium supplements throughout the day. Remember, you’ll have to take a ton of it in order to balance out even a small amount of sodium. (Talk to your doctor for more guidance on how to supplement with potassium. Although, most doctors don’t understand these ratios very well. You may have better luck speaking to a doctor who specializes in something like sports medicine).
One other thing worth noting: heavy cardio causes you to sweat; sweat is loaded with sodium. Adding a little bit of salt to your post-workout bottle of water (like 1/2-tsp, or roughly 500 mg) can help restore electrolyte balances as well.
Too Many Carbs
Water is required in order to process carbs. So, the more carbs you eat, the more water your body will retain in order to properly process the carbs. Sugar, especially, will throw your system into a water-retention panic (especially if you’re not used to eating sugar).
This is why most people who start on a relatively low-carb diet report losing 5 or more pounds in the first week. Suddenly, their body releases a TON of water-weight as it’s no longer required to process the volume of carbs that were once being eaten.
It’s also the reason that a single cheat-day can cause you to gain more weight than the combined total of the food itself. (Eat an extra 100 g of carbs in a single day and you may find that the scale goes up 2-3 pounds). Fortunately, the weight falls right back off again once you go back to normal eating.
The Female Monthly Cycle
Yup. Being on your period can cause the scale to fluctuate anywhere from +/- 3 to 12 pounds in a single day. In fact, that “time of the month” can cause havoc on the scale as your body holds on to and eventually releases large amounts of water.
It’s worth reiterating that while this is happening, you can and are still burning fat if your diet is on-point. So, it’s nothing more than an emotional setback. During this time, it’s worth paying attention to other factors to help indicate that you’re in fat-burn mode.