How Ketosis Works

Under normal dietary conditions, the body primarily uses glucose — derived from carbohydrates — for energy.

When carbohydrate intake becomes extremely low, several metabolic changes occur:

1. Glycogen stores in the liver and muscles become depleted.
2. The liver begins breaking down fatty acids.
3. Ketone bodies are produced as an alternative fuel.

The main ketones produced in the liver include:

• acetoacetate
• beta-hydroxybutyrate
• acetone.

These molecules circulate in the bloodstream and can be used by many tissues, including the brain.

Metabolic scientist Dominic D’Agostino explains:

“Ketones provide an efficient fuel for the brain and may offer metabolic advantages in certain conditions.”

Normally, ketone levels in blood remain around 0.2–0.5 mmol/L. When they rise to 0.5–5 mmol/L, the body enters nutritional ketosis.

It’s important not to confuse this state with Diabetic Ketoacidosis — a dangerous condition that occurs primarily in people with uncontrolled diabetes.

Why the Keto Diet Can Promote Weight Loss

One reason the ketogenic diet is widely used for weight loss is its impact on metabolism and appetite.

When carbohydrates are reduced:

• insulin levels drop
• fat burning increases
• appetite hormones may change.

Lower insulin levels reduce fat storage and allow the body to access stored fat more easily.

Another important factor is appetite regulation. Many people naturally eat fewer calories on keto because fat and protein tend to be more filling.

Nutrition scientist Stephen Phinney notes:

“One of the most consistent findings in ketogenic diet research is a spontaneous reduction in appetite.”

Researcher Jeff Volek adds:

“Ketones appear to influence hunger hormones such as ghrelin, which may help people maintain lower calorie intake.”