What the Liver Actually Does — and Why It Matters on Low-Carb Diets by Roxana Soetebeer, MPHC, NNP, MHP, PFC
What the Liver Actually Does — and Why It Matters on Low-Carb Diets
If you've ever been told that your body "needs" carbohydrates to survive, here's something to sit with: your liver makes glucose. It always has. It always will. That's not a backup plan. That's the design.
It doesn't matter if you're asleep, fasting, or eating nothing but steak. Your liver keeps your blood sugar stable. That's one of its jobs, and it's really good at it. So the idea that you need to "eat carbs for energy" is not just outdated, it's biologically wrong.
Let's walk through what your liver actually does, why this matters for low-carb, fasting, and carnivore diets, and how things go off the rails in insulin resistance and liver disease.
The liver has two main ways of keeping blood sugar stable:
- Glycogenolysis: This is when your liver breaks down stored glycogen (a form of glucose) and releases it into the bloodstream. The liver typically stores about 80 to 100 grams of glycogen, enough to keep blood glucose stable for 12 to 24 hours in a fasted state.
- Gluconeogenesis: This is when your liver makes new glucose from non-carb sources: amino acids (from protein), glycerol (from fat), and lactate (from muscle metabolism).
The second one, gluconeogenesis, is the star of the show on keto, carnivore, or during fasting. It's demand-driven. Your body doesn't just pump out extra sugar for fun. It makes exactly what it needs to fuel the brain, red blood cells, kidneys, and a few other glucose-reliant tissues. Everything else runs on fat or ketones.
This is why humans can survive weeks without food. The liver keeps the lights on.
When you drop carbs, your body doesn't fall apart. It adapts. The liver takes over glucose production, ketones are made from fat, and you enter a metabolic state humans have been cycling through for millions of years.
- On keto, your glucose needs are met by gluconeogenesis.
- On carnivore, you get plenty of amino acids for that process, plus fat for fuel.
- During fasting, glycogen stores drop, and the liver steps in to make the glucose your body still needs.
None of this is a crisis, an emergency, or stress. It's how we're built.
The problem is that most people have never experienced this because they've been locked in carb-burning mode their entire lives. Their liver can't regulate properly because their insulin is too high, their mitochondria are sluggish, and their fat metabolism is dysfunctional. So when they try low-carb or fasting without preparation, it feels like withdrawal, because it is.
Here's where it gets complicated.
In insulin-sensitive people, the liver stops making glucose when it's not needed. Insulin tells it, "Hey, we've got fuel coming in, slow down the glucose production." But in insulin-resistant people? The liver doesn't listen. It just keeps pumping out glucose. It does it even when blood sugar is already high.
To make it worse, the dawn phenomenon is more pronounced. Everyone has it. It's a natural cortisol rise early in the morning that increases liver glucose output, to get us up and running in the morning. In healthy people, insulin quickly compensates. In diabetics, it doesn't, and the fasting glucose stays high until they eat.
This is the source of confusion and frustration: Why is my glucose high and comes down as soon as I eat? The body doesn't see high glucose as an emergency. But when we eat, glucose goes even higher, which is then treated as an emergency and triggers a larger insulin response. That extra insulin finally brings glucose levels down. So, no, that does not mean we should eat to bring our glucose down. It's just one more telltale sign that the liver is dysregulated.
Sometimes, doctors misinterpret this too and tell patients to eat more carbs. That advice might make sense in a hypoglycemic crash, but not when glucose is high. The liver isn't starving; it's out of control.
If your liver is overproducing glucose, it's not because you didn't eat enough carbs. It's because it is dysregulated, and insulin isn't working.
The liver is the organ that can take the most abuse and still come out whole with dietary intervention, but only to a certain point. When the liver stops working well, things can get serious fast. Early stages are usually silent. That's part of what makes liver disease so dangerous. Here's the progression:
- NAFLD (Non-Alcoholic Fatty Liver Disease): Fat builds up in liver cells. Usually caused by excess energy intake, especially from refined carbs and fructose. In most cases, completely reversible with diet change and weight loss.
- NASH (Non-Alcoholic Steatohepatitis): Fat plus inflammation. The liver is in trouble, liver enzymes go up. Still reversible, but harder—needs strict intervention.
- Fibrosis: Scar tissue begins forming. The liver is trying to repair itself, but damage continues. Can stabilize or even partially reverse with proper treatment.
- Cirrhosis: Widespread scarring, liver function drops. Can lead to liver failure, cancer, or death. Irreversible, but progression can be slowed.
- End-Stage Liver Disease / Failure: At this point, you're looking at a transplant. The liver can't do its job.
Fatigue is the pain of the liver. It's an early sign that something isn't right. If your energy is gone and nothing else explains it, get your liver checked. Better to be safe than sorry.
This is not medical advice. Talk to your medical provider before changing your diet.
- Stop feeding it excess sugar. Fructose is mostly processed in the liver. In excess, it turns to fat.
- Fix your hyperinsulinemia. Chronically high insulin drives fat storage and disrupts glucose regulation.
- Eat real food. Protein and natural fats do not harm the liver. They're essential.
- Be cautious with seed oils. The evidence is still debated, but excessive omega-6 intake may impair mitochondrial function.
- Fasting. Give your liver a break. Time-restricted eating or longer fasts can reduce liver fat.
- Lose visceral fat. That's the bad fat around the midsection. It chokes the organs and is strongly linked to liver dysfunction and glucose dysregulation.
The liver is incredibly resilient. It can regenerate. But you have to stop overwhelming it first.
Your liver was built to fuel you, even when food isn't around.
That's not an emergency. It's the original design.
You didn't break. You just didn't know how the system works. Now you do.
Eat like it matters,
Coach Roxana
Written by Roxana Soetebeer, MPHC, NNP, MHP, PFC
Published May 3rd, 2025
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