Why 20g of Carbs? The Science Behind the Limit

If you've spent five minutes researching the ketogenic diet, you've seen the magic number: 20 grams of net carbs. But why not 50g? Or 100g? In 2026, our understanding of glycogen depletion explains why this threshold remains the gold standard for triggering the metabolic switch to ketosis.

The Glycogen Depletion Phase

Your body typically stores about 400-500 grams of glycogen in the liver and muscles. To enter ketosis, liver glycogen must be nearly exhausted. For the vast majority of human metabolic profiles, consuming more than 20-30g of carbs provides enough glucose to stall the liver's production of ketones. By staying under this limit, you force your mitochondria to look for an alternative fuel source: fat.

Net Carbs vs. Total Carbs

It is crucial to understand the difference between net carbs and total carbs. We calculate Net Carbs by taking the Total Carbohydrates and subtracting the dietary Fiber. Because fiber does not trigger an insulin response or contribute to blood sugar spikes, it does not count toward your metabolic ceiling. This means you can still enjoy high-fiber greens and cruciferous vegetables while maintaining a deep state of ketosis.

Precision tracking is the only way to guarantee results in the early phases of keto-adaptation. Using our tools to find your specific BMI and activity level ensures that you don't accidentally exceed your biological carbohydrate threshold.