Understanding Your Body's Natural Fat-Burning State
Ever wondered how your body can switch from burning carbs to burning fat? It's called ketosis - and understanding it is the key to making the keto diet work for you.
Think of your body like a hybrid car - it can run on two different fuels
Default fuel from carbs
Burns sugar for energy
Stores excess as fat
Activated by low carbs
Burns fat for energy
Produces ketones
Ketosis is a natural metabolic state where your body switches from using glucose (sugar) as its primary fuel to using ketones - molecules produced when your liver breaks down fat.
This isn't some new diet trick - it's how humans survived for thousands of years when food was scarce. Your body is designed to do this.
When you drastically reduce carbs, your glucose stores deplete within 3-4 days. Your body then turns to fat - both dietary fat and stored body fat - breaking it down in the liver to produce three types of ketones: acetoacetate, beta-hydroxybutyrate (BHB), and acetone. These ketones can fuel almost every cell in your body, including your brain.
Your body uses up stored glucose (glycogen) from liver and muscles
Ketone production begins as fat breakdown increases
Full ketosis achieved - body efficiently burning fat for fuel
Fat-adapted - your body becomes highly efficient at using ketones
To enter and maintain ketosis, you need to dramatically shift what you eat:
This typically means keeping carbs under 50g per day (some aim for 20g). For perspective, that's less than a single bagel or two bananas.
Stanford researchers recently discovered a new metabolic pathway - BHB-amino acids - that explains why ketosis suppresses appetite and promotes weight loss. This "shunt pathway" directly links ketones to energy regulation in ways scientists didn't previously understand.
During the first week, some people experience temporary symptoms as their body adapts:
This usually passes within a week. Staying hydrated and keeping electrolytes up helps significantly.
Nutritional ketosis is safe and different from diabetic ketoacidosis (DKA). In ketosis, ketone levels are controlled and blood remains at normal pH. DKA is a dangerous condition in diabetics where ketones build to harmful levels. If you have diabetes, consult your doctor before starting keto.
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