How to sleep less and feel rested?

When a person switches to a keto or low-carbohydrate diet, a whole range of metabolic changes occurs in their body, which directly affects the quality and duration of sleep.

Reduction of glucose and insulin fluctuations. With a traditional high-carbohydrate diet, there are often nighttime "sugar swings": after dinner, glucose rises, then falls, sometimes below normal, causing micro-awakenings and restless sleep.

On keto, blood glucose levels become stable, eliminating nighttime "swings" and reducing the number of awakenings.

Increase in ketone bodies. Ketones (beta-hydroxybutyrate and acetoacetate) cross the blood-brain barrier and serve as "clean" fuel for neurons. They reduce oxidative stress and increase mitochondrial efficiency. This makes sleep more effective: the brain recovers as well in less time as it does with longer sleep on a carbohydrate diet.

Influence on neurotransmitters:

• The ketogenic diet increases the level of GABA (gamma-aminobutyric acid) — the main inhibitory neurotransmitter. This makes sleep deeper, reduces nighttime anxiety, and the number of awakenings.
• The level of glutamate decreases, the excess of which is associated with excitation and insomnia.
• The levels of serotonin and melatonin normalize as tryptophan metabolism stabilizes.

Reduction of cortisol levels at night. High carbohydrates in the evening → insulin spike → nighttime drop in sugar → cortisol release to maintain glucose levels. This interferes with deep sleep.

On keto, this chain is disrupted, and cortisol interferes less with recovery at night.

Increase in adenosine. When using fats and ketones as fuel, adenosine — a molecule that induces drowsiness and regulates sleep depth — accumulates more actively in the brain. This leads to a quicker onset of the "full recovery" state.

Thus, on keto, the body experiences deeper, higher quality sleep with more phases of slow-wave sleep (stages 3–4). Therefore, total sleep time may decrease by 1–2 hours, but the feeling of alertness and recovery remains even higher than with longer sleep on a carbohydrate diet.

This is not "sleep deprivation," but rather sleep optimization: the brain and body perform restorative processes more efficiently in less time.