“Our cells, organs, and brains are all made of fat and need high-quality fat to function optimally. Fat is also the basis for the lining of your nerves, called myelin, which allows electricity to flow efficiently…When you eat enough of the right fats without excess carbs, your body learns to efficiently burn fat for fuel and to form healthy cell membranes.” — Dave Asprey

生酮飲食 (Ketogenic Diet) — 顯著降低碳水化合物攝取、以脂肪為主要能量來源的飲食模式。最初於 1920 年代，本來是兒童癲癇的治療方案，後來才被廣泛應用於減重和代謝健康改善。

酮體 (Ketone Bodies) — 肝臟在脂肪酸分解過程中生成的有機化合物，可作為替代能源

酮症 (Ketosis) — 身體轉而以脂肪作為主要能源的代謝狀態

生酮作用 (Ketogenesis) — 指脂肪酸分解生成酮體的生化過程

How Ketosis Works

When carbohydrate intake drops below a certain threshold (~20–50g net carbs/day), the body depletes its glycogen stores and shifts into a fat-burning metabolic state. The liver converts stored body fat and dietary fat into ketone bodies (acetoacetate, β-hydroxybutyrate, and acetone), which can cross the blood-brain barrier as an alternative fuel source for the brain.

This metabolic flexibility — the ability to switch between glucose and ketones — is the underlying mechanism. The transition typically takes 2–7 days, a period often referred to as the “keto adaptation” phase.

Related: fasting induces ketosis through a similar mechanism of carbohydrate restriction.

The Keto Flu & Electrolytes

During the initial transition, many people experience “keto flu” — a cluster of symptoms including fatigue, headache, brain fog, irritability, and muscle cramps. The primary cause is electrolyte depletion: as the body flushes out glycogen, it also excretes bound water and electrolytes (sodium, potassium, magnesium).

Key countermeasure: Take extra salt (sodium). Unlike a standard diet where salt restriction is advised, the ketogenic diet significantly increases sodium requirements.(salt.md).

• 補充足夠的電解質（鈉、鉀、鎂）是預防「酮流感」最有效的方法
• Consider magnesium and potassium supplementation if symptoms persist

MCT Oil

• 是一種分餾椰子油。MCT stands for “Medium Chain Triglycerides (中鏈脂肪酸)” — fatty acids with a shorter molecular structure that allows for more rapid digestion and direct absorption via the portal vein to the liver.
• Unlike LCTs (long-chain triglycerides), MCTs bypass the lymphatic system and are rapidly converted into ketones, making them a powerful tool for elevating blood ketone levels quickly.
• Provides several cognitive and metabolic benefits:
  • Better mental clarity and focus
  • Enhanced satiety
  • Improved insulin sensitivity
  • Increased ketone production
  • Reduced risk of heart disease
• Is better absorbed after being emulsified (乳化)

防彈咖啡 (Bulletproof Coffee)

A popular breakfast replacement / fasting-friendly beverage in the keto community.

• 黑咖啡 — provides caffeine and antioxidants
• 無鹽草飼奶油 (unsalted grass-fed butter) — rich in butyrate and CLA (conjugated linoleic acid)
• 椰子油 or MCT 油 — adds ketone-boosting medium-chain triglycerides