7 Water Myths and Facts

New keto’ers occasionally ask how to track water in the Senza Food Journal. We decided not to build this feature into the app, and that’s by design. We’ve noticed that when people follow conventional wisdom of “eight glasses a day” or “more is better,” they can introduce unintended complications, including a bad case of the keto flu.

While staying hydrated is very important, and your need for water does increase with the transition to ketosis, more often we hear about problems with over-hydration and electrolyte depletion. 

To clear up the confusion, Coach Madisen decided to dig into the myths and facts around keto and water intake, so you can develop an approach that works for your individual hydration needs.

Water Myth #1: I need to drink half my body weight in ounces each day.

Water Fact #1: Your optimal water intake is unique to you and varies day by day. 

Just like caloric intake, ideal water intake depends on the person and the circumstances. Fixating on a set amount can leave you either over- or under-hydrated. Many factors determine how much water you need on any given day, including:

  • Your height and weight 
  • Time of year
  • Temperature 
  • Sweating
  • Stress levels
  • Digestion 
  • Ketone levels
  • Sodium intake
  • Food quality
  • Medications
  • Activity level

Given all these variables, the best way we’ve found to gauge fluid intake is to tune into your normal thirst cues, aim for almost transparent urine several times per day, and make sure the water that you’re drinking has sufficient levels of minerals. (More on that topic below...)

Water Myth #2: My water needs won’t change when I start keto.

Water Fact #2: Your hydration needs likely will increase when you switch into the state of ketosis, but you need to be careful not to drink so much that you flush out electrolytes that are needed to run the body’s metabolic processes.

Once you begin producing ketones and using fat as the primary source of energy, your glycogen levels will drop as your body uses up its stored carbohydrates. Each gram of glycogen holds 3 grams of water, and the body on average stores 600 grams of glycogen at any given time. As you burn through this glycogen in the transition to ketosis, you will in turn, lose fluids (around 4 lbs worth) and the minerals contained in those fluids, which you’ll need to replenish. This initial rapid loss of water weight is also known as the “whoosh” and typically happens within the first week of the keto journey.  

Water Myth #3: I can get all the electrolytes I need with good food choices.

Water Fact #3: You’ll likely need to supplement sodium, potassium, and magnesium to avoid deficiencies with keto.

Electrolytes are essential minerals that regulate many critical processes in the body. For example:

  • Sodium helps with fluid balance, hydration and muscle contraction.
  • Potassium helps with blood pressure and the beating of your heart.
  • Magnesium helps with muscle contraction, energy, heart function, calm mood and sleep.

We absorb electrolytes through food and drink and excrete them through sweat, urine and feces. Electrolyte deficiency can lead to flu-like symptoms, including fatigue, headaches, dizziness, muscle cramps, and more.

What makes us deficient in electrolytes?

Glad you asked! Due to modern day life, dietary habits, excessive stress, industrial agriculture and food processing, electrolyte concentration and absorption from common foods has declined. In particular, magnesium content in our food has dropped by upwards of 80 percent compared to 50 years ago, meaning we don’t absorb the amounts we used to get from fresh, whole foods. 

At the same time, the keto way of eating increases your need for these minerals due to loss of fluids as you transition from burning glycogen to burning fat for energy. This is why we follow the advice of keto experts and recommend supplementing with at least 5000 mg of sodium, 1000 mg of potassium and 400mg of magnesium as you get started with keto. You can take these minerals separately as capsules or powders, or try a popular all-in-one brand like Redmond ReLyte, Keto Vitals, or Ultima Replenisher. Just be sure to avoid brands that contain sugar, aspartame or sucralose. 

For more tips on keto and electrolytes, see Senza FAQs for the Keto Beginner on The Planet Keto Blog. Be sure to check out Coach Madisen’s Electrolyte Drink in the Senza Recipe Box, too!

If you’re curious about how your daily mineral intake from foods is trending, you can check the Senza Trends page and change the view to Sodium or Potassium. (Magnesium is not available as a graph because too few labels include it for an accurate picture of your intake.)

How do you know if you need more electrolytes?

  • Experiencing flu-like symptoms in the transition to keto

  • Heart palpitations or racing heart (likely potassium deficiency)

  • Feeling shaky, dizzy or weak like you’re going to pass out (likely sodium deficiency)

  • Headaches, brain fog, or migraines (likely sodium deficiency)

  • Initial weight loss in the first week of keto (usually due to a loss in water weight)

  • Leg or other muscle cramps, such as getting Charley horses at night - (likely magnesium deficiency)

  • Trouble with constipation and bloating

Water Myth #4: Any water is fine for hydration. 

Water Fact #4: Just like food quality, water quality ranges dramatically.

All water is not created equal! Tap water, depending on where you live, can be loaded with pharmaceuticals, fluoride, pesticides, herbicides, volatile organic compounds (VOCs), chlorine, and other contaminants. Most bottled water contains harmful chemicals due to the leaching of plastic into the water. These contaminants can interfere with hormone balance, liver function and overall, add to the toxic load of the body. 

The best sources of water include spring water and reverse osmosis (RO) water, ideally stored in glass. If you decide to opt for RO filtered water, be sure to add back electrolytes and trace minerals with a supplement like ConcenTrace drops, sourced from the Great Salt Lake, since RO water has filtered out all of the minerals. 

Water Myth #5: I should drink at least eight glasses of water a day, even if I’m not thirsty.

Water Fact #5: You can go by your own variable thirst cues to guide your water intake.

When it comes to water intake, more isn’t necessarily better. You don’t want to override your normal thirst cues by drinking water when you don’t need it. That said, don’t wait until you’re ready to chug a gallon of water before you have a drink. It’s important to tune into those subtle cues and expect to need some added fluids in the morning, after a workout and on hot summer days. 

Water Myth #6: It doesn’t matter when I drink water.

Water Fact #6: Water intake should be spread throughout the day and limited at mealtimes.

Make a point of drinking fluids several times a day, but avoid water, especially cold water, 30 minutes before your meals to prevent dilution of stomach acid, which impairs digestion. 

Water Myth #7: All fluids are hydrating.

Water Fact #7: Some drinks can cause dehydration and increase your need for water.

You don’t have to drink plain water all day long, but keep in mind that not all fluids are hydrating. Alcohol in particular has a strong diuretic effect on the body and will cause you to lose more fluid than you drank. It’s also problematic because the body has to process alcohol before anything else, meaning it delays fat-burning temporarily.

Coffee has been the subject of much debate, and the latest science seems to have concluded that while there is a mild diuretic effect on the body with moderate consumption - for most people, the amount of fluid you lose doesn’t exceed the amount of the drink. (This advice changes, however, if you exceed 600mg of caffeine, at which point dehydration kicks in, according to this study.)

Take a mindful approach to hydration when drinking caffeinated beverages, and try to notice whether you experience an increased thirst with those choices. 

Keto & Hydration Wrap-up

Water is the most basic need for survival, and quality matters. Your requirements will change with keto, but try not to overthink it -  and you certainly don’t need to track it.

Learn More about Getting Started with Keto


Content provided by Senza is not medical advice. It is intended for informational and educational purposes only.