how our body burns fat?
In: Biology
I always thought that cold environments are the number one reason to burn fat, but hey, explain to me aswell
When your body needs energy, it uses fat like a car uses fuel. Fat is stored in your body like a little energy pack. When you run, play, or don’t eat for a while, your body opens those packs and turns the fat into energy to help you keep going. As your body uses up the fat, the packs get smaller, which is how you lose fat.
Okay so you have 3 main energy systems, each providing energy for different kinds of activity. Burning any calories is about oxidation/chemical reactions for energy.
You exhale the byproducts. Your breath is like the tailpipe of a car. When you lose weight, you’re physically exhaling it.
– The phosphagen system is used for short, high-intensity efforts (up to 10 seconds) and doesn’t rely on fat, as it primarily uses stored ATP and creatine phosphate.
– The glycolytic system (up to 2 minutes of moderate intensity) breaks down glucose for energy, with minimal fat involvement.
– The oxidative system is used for longer, lower-intensity activities and primarily relies on fat, alongside carbohydrates, for sustained energy production through aerobic metabolism.
When fat is used for energy it is converted into fatty acids which are oxidized in cells or the fatty acids are converted to glucose via gluconeogenesis so that glucose-using things like your brain can burn it.
You are made up of billions of cells. These cells need energy to perform their daily cell activities. Energy for them is in the form of a molecule ATP. Primarily this is ATP is generated in the mitochondria (hence why it is the powerhouse of the cell).
A fat molecule is a molecule made up of Carbon, Hydrogen and Oxygen atoms that are bonded together. By breaking these bonds, energy is released, which allows the formation of ATP. The processes of breaking these molecules is quite complex. It involves 3 steps, which are Lipolysis, The Krebs Cycle and Oxidative Phosphorylation. This is a little too detailed for ELI5 so you can look it up if you want to read more.
As the Carbon, Hydrogen and Oxygen is released from breaking the molecule apart, they form new molecules. Carbon dioxide (CO2) which you breathe out, and Water H20 which is lost through sweat, breath moisture or urine.
The body primarily likes to use glucose or other carbohydrates for energy production which uses very similar pathways (Glycolysis -> Krebs -> Oxidative phosphorylation). Thus you need to be deficient in carbohydrates to encourage the body to burn fat.
An intermediate step can get overwhelmed when using fat metabolism. When this happens it results in the formation of another molecule called ketones. Whilst these Ketones are not inherently bad, they can lead to a form of acid in the blood called keto acidosis if overproduced. Keto diets specifically focus on the generation ketones from fat breakdown.
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