Electrolyte Absorption: What you need to know

As a mostly fat-fueled guy, I’m a big believer in only using glucose when I need it. The truth is, I don’t want a hit of sugar every time I supplement sodium, potassium, or magnesium. Many of my followers feel the same way.

You might have heard that adding sugar to electrolytes boosts hydration - this isn’t false. Glucose does help transport sodium, chloride, and water across the intestinal barrier.

Because of this, some claim you need glucose for proper hydration. Without glucose, they say, you’ll be short on both electrolytes and energy. But these folks are confused about the science.

While glucose may boost performance in some situations—like when I roll with 25-year olds—most situations don’t call for it.

Yes, you can hydrate and power your body just fine without glucose. I’ll explain more later after we cover the basics of hydration.

Why You Need Electrolytes

Along with water, you also need sodium, calcium, magnesium, potassium, and chloride to hydrate properly. These minerals—called electrolytes—regulate a staggering number of processes in the human body. For instance:

  • Sodium helps with fluid balance and muscle contraction
  • Potassium helps with blood pressure and the beating of your heart
  • Magnesium helps with muscle contraction, heart function, and even anxiety

We absorb electrolytes through food and drink, and excrete them through sweat, urine, and feces. If one side of this equation becomes skewed (from heavy sweating, diarrhea, etc), an electrolyte imbalance can result. Electrolyte deficiency in particular leads to symptoms like fatigue, headaches, and muscle cramps.

If you don’t take electrolytes after sweating, you’re guaranteed to feel lousy. This is especially true if you follow a low-carb or ketogenic diet.

Why? Because your kidneys excrete more sodium in a low-insulin (read: low-carb) state. Many folks don’t realize this.

I only realized it myself fairly recently after my coaches at Ketogains helped me dial in my electrolytes. When I added more salt to my low-carb diet, not only did my jiu jitsu performance increase—my everyday energy increased too.

Okay, you’re on board with electrolytes. But what about the whole glucose hydration thing?

Do You Need Sugar To Absorb Electrolytes?

The short answer is no.

Yes, glucose helps you absorb sodium, chloride, and water. But no, glucose is not necessary for hydration.

Let’s quickly cover the history here. Then we can unpack the truth about glucose and electrolytes.

History of Oral Rehydration Therapy

Take a little trip back to 1960. That’s when Dr. Robert Crane proposed his “cotransport hypothesis” for sodium and glucose.

Now solid science, the idea is that sodium and glucose join forces to increase one another’s absorption in the gut. This “cotransport” of glucose and sodium through the intestine is mediated by proteins called SGLT1 and SGLT2 in your gut. (As an aside: an FDA-approved class of diabetes drugs called SGLT2 inhibitors work by reducing glucose absorption to lower blood sugar levels. Another group of drugs called SGLT1 inhibitors have shown similar effects, but are still awaiting FDA approval).

Clinically, administering a mixture of glucose and sodium is called oral rehydration therapy (OHT). OHT has rehydrated countless people after extreme bouts of diarrhea, often due to cholera. According to some sources, OHT has saved millions of lives.

So yes, adding glucose to an electrolyte solution can increase hydration. It’s a useful tool in the disease-management toolkit.

But it’s not the only way to hydrate. Good news for those of us limiting sugar.

Other Ways To Absorb Sodium

First of all, you can absorb sodium—all by itself—in the small intestine. This happens either passively through diffusion, or actively with the help of a sodium transporter.

It’s easier, however, for your gut to absorb sodium with a cotransporter. The process requires less energy than absorbing sodium alone, and therefore is “preferred”.

You already learned about the sodium-glucose cotransport system. Yes, having glucose present increases the passage of sodium through intestinal cells.

But glucose isn’t the only game in town. Here are some other sodium cotransporters.

  • Butyrate: Your gut bacteria create butyrate (a short-chain fatty acid) when they digest fermentable fiber in your gut. Butyrate helps you absorb both water and sodium.
  • Amino acids: Eating protein? You’re absorbing more sodium. A number of amino acids are carried through the gut across sodium-dependent transporters.
  • Phosphorous: The sodium-phosphate cotransporter transfers electrolytes through cells in the large and small intestines.R Phosphorus is abundant in meat, dairy products, and beans.
  • Potassium and chloride: These electrolytes join forces with sodium via Na-K-2Cl transporters all throughout your body.
  • Beta hydroxybutyrate (BHB): When you restrict carbs, your blood sugar and insulin levels drop and you start burning fat. The ketone body BHB—a product of this fat burning—serves as a cotransporter for sodium.

To really hammer this home, let’s see what happens to sodium when you restrict glucose completely.

Sodium Levels With No Glucose

When someone says you need sugar to absorb electrolytes, I like to reference a super interesting study from back in the day.

Granted, it was published in the 70s and only had one subject. But I think it says a lot about fasting, ketones, and hydration.

In the study, researchers took a 456 pound man and fasted him for 382 days. Except for a few multivitamins and electrolyte supplements—he only drank water.

At the end of the fast, the morbidly obese gentleman was down to a svelte 180 pounds. He suffered “no ill effects” from the fast, according to the authors.

That alone is incredible. But I want to double click on his blood electrolyte levels over the course of the fast.

As expected, his serum electrolytes dropped initially. But after 100 days, his sodium and potassium stabilized to more or less normal levels. This was sans supplementation for most of the study.

What happened, I believe, is that ketones—massive amounts of BHB generated during the fast—helped our man absorb his sodium. Other studies also show a ketogenic diet to be perfectly compatible with healthy sodium levels.

This wouldn’t happen if you needed glucose to absorb electrolytes,

Sugar For Energy?

Let’s talk carbs for exercise performance now. On this topic, I often hear people say something like:

Sure, low-carb diets work for low or medium intensity exercise, but you need carbs to fuel harder efforts.

This makes logical sense. Intense exercise is glycolytic, and forces your cells to use glucose for energy. If you do enough glycolytic exercise, you deplete your stored glucose—and glycogen stores must be refilled. That’s why the standard advice is to “carb up” before track workouts, marathons, jiu jitsu sessions, etc.

But here’s the thing. You have glucose in your blood on a low-carb diet, just less of it. Fatty acids—not glucose—cover most of your energy needs in fat-adapted state.

That includes exercise needs. Ketogenic diets, in fact, have a glycogen-sparing effect.R In other words, you can exercise longer before depleting your stored glucose.

Recently researchers split athletic men into two groups—cyclical keto (CKD) and standard keto (SKD)—and put each group on an eight-week weight lifting and sprinting program. Hard exercise. The SKD group ate strict keto for the duration, while the CKD group ate high-carb two days per week.

Surprisingly enough, carb cyclers saw no performance benefit. Apparently, the extra glucose didn’t help these fat-adapted athletes.

As a side note: for body composition, standard keto was the clear winner. More fat lost, more muscle retained.

To be clear, these effects were seen in resistance-trained men. Maybe other populations—like athletic women—would fare better on a carb cycling protocol. There’s plenty of anecdotal evidence that a cyclical or targeted ketogenic diet works best for some people.

Depending on my level of training, that includes me.

My Electrolyte Protocol

I train Brazilian jiu-jitsu three to five times per week. Before each session, I take a stick of LMNT electrolytes in 16-24 ounces of water. This replaces the sodium, potassium, and magnesium I know I’ll lose through sweat.

Most of the time, I only take electrolytes. Totally fat-fueled. But depending on my competition and training duration, I occasionally use targeted doses of glucose to augment my performance. (You can easily find glucose powder or tablets online).

Robb’s Electrolyte Protocol for Training:

Jiu-jitsu training level LMNT Glucose

Standard drilling

1 stick before class


Rolling with guys my age

1 stick before class

5-10 grams per hour

Rolling with 25 year olds

1 stick before class

15-20 grams per hour

Training on a hot day

1 or more sticks

As needed

Play around with my protocol to suit your needs. If you’re training hard, it makes sense to have glucose on hand—but it shouldn’t be an everyday thing.

Electrolytes For Low-Carb Living

To recap my main points:

  • Electrolytes are essential for health, and low-carbers need more of them
  • Glucose can help you absorb electrolytes, but you don’t need glucose to absorb electrolytes
  • Butyrate, amino acids, BHB, and many other molecules also cotransport sodium into your cells
  • One man maintained sodium levels during a 382 day fast without consuming any glucose
  • Fat can fuel most exercise, though small doses of glucose may help with long or intense efforts—like rolling with guys half my age.

Here’s the thing. If you’re training in a low-carb state, you probably need more electrolytes. Especially sodium. But glucose? That varies greatly from person to person, regimen to regimen.

That's why my coaches, Tyler and Luis, originally developed an electrolyte protocol and ultimately what led us to launch LMNT. Our electrolyte blend lets you take sodium, potassium, and magnesium—the real keys to hydration—apart from sugar.

Happy hydrating and stay salty ⚡