How your body is like a car....

iAlly

Hi Fitness Pals

This was a blog i just wrote but I thought I'd post it here as well

Firstly here's some music to listen to while you read

http://www.youtube.com/watch?v=DUDtFdnn9oQ

Settle in, buckle your belt and I'll take you for a spin.

A lot of crap gets written on the forum and I want to lay out a few things here for reference. Lots of you will already know this stuff but some people are new to weight loss and could do with some info like this.

First the boring science part...

1. Your body is an engine that needs a form of sugar to power it.

The sugar is called glucose.

2. Glucose is dissolved in your blood and pumped round your body. This is how it is delivered to all the different parts of your body that need it.

All over your body the cells are converting the glucose in your blood into the energy they need to run and repair themselves.

3. The glucose gets into your blood by digesting food.

Digestion is where the food you eat gets broken down into glucose so your body can use it. In effect your body is one big recycling factory. It takes in fat, protein, complex carbohydrates and simple carbohydrates (aka sugars) and breaks them down into the little glucose molecules, These molecules are then passed through the gut into the blood stream.

4. When we eat food we can end up with too much glucose in our blood. When this happens the body first tries to convert spare blood glucose into a complex carbohydrate called glycogen.

This glycogen is stored in the liver and in the muscles. If you've been eating a lot you could store up to and over 1lb of glycogen ready to be used quickly when the body needs it. Importantly water binds to glycogen and you will have 4 lbs of water stored alongside it. Glycogen is the body's medium term energy storage solution.

6. If blood sugar is too low the body converts the stored glycogen back into glucose.

If you don't eat for a while or start to exercise the glucose in your blood gets used up and levels start to drop. The body turns to it's short term store of glycogen to get more glucose. The water is released and you'll pee more (unless you sweat it out). If you use all your glycogen i.e. you are running a marathon or have not eaten for days you'll eventually reach exhaustion.

7. If your blood glucose levels are high AND your glycogen store is full your body will start to convert glucose into fat.

Fat is the body's solution for long term storage of energy.

8. If your glycogen store is low or empty AND your blood glucose levels are low your body will convert fat into glucose.

What does all this mean....

There are 3 main fuel storage solutions mother nature has given us. Fat, Glycogen and Blood Glucose.

Blood Glucose is very short term storage. Glycogen is medium term storage. Fat is long term storage.

To make an analogy with the motor car - the Blood Glucose is the gas that's in the engine getting used to keeping the car running, the Glycogen is the gas in the gas tank and the Fat is a trailer full of gas that you've been towing around with you in case you can't find a gas station!

When you start a new diet in the first week you initially reduce the body's medium term store of fuel. You burn your glycogen store and when you do you release the water that is tied up in the storage. The car has gotten lighter but you've not used much of the fat that you've been towing on the trailer. That's the bad news - you might lose 5 lbs but you've not burned 5 lbs worth of fat. Sorry

In the following weeks, if you've been dieting for some time and your glycogen levels are low when you fall off the wagon and go on a spurge you replenish your body's medium term store. And for every part of glycogen you store away you also store 4 parts water with it. So when you go crazy and eat a pizza you have filled the gas tank with glycogen (and 4 parts water) and you wake up the next morning 5 lbs heavier. Here's the good news - you have not gained 5 lbs worth of fat.

Your gas tank will be able to hold anywhere between 250-700 grams of glycogen depending on how much muscle you have. Glycogen is stored in the liver and your muscles. If you have lots of muscles you've got a bigger gas tank. 250 grams of glycogen equates to about 1000 calories and 700 equates to 2800 calories. So if you were a large muscle man and were total exhausted you could eat 2800 extra calories over your BMR before your body would think about making fat. You'd simply replenish your glycogen store.

The solution, stop filling the car from the gas station when you are towing a trailer full of gas around with you. And especially don't overfill the tank. It's only with repeated overeating that you'll gain fat. The occasional step off the diet won't hurt you. If you see the scales jump go for a work out and burn some of the gas in the tank.

Remember don't let the gas tank get empty or the engine won't work. The recommended MINIMUM calories for men is 1500 and 1200 for woman. If you go bellow this your metabolism will slow, your car will be slow and won't burn fuel efficiently.

I hope you've enjoyed this blog and it's been of some use to you. What is it they say... your mileage may vary. Take from it what you can and thanks for reading.

Cheers Ally

P.S. It's called petrol not gas but I thought I'd make it easy for my American pals

I mean cmon it's not even a gas it's a liquid but that's for another day haha

ArchyJill

That was a fun read! Thanks!

dore0021

Great Job!

Ford4x4lady

Very well put & thank you so much.
Love your insite

MacMadame

The recommended MINIMUM calories for men is 1500 and 1200 for woman. If you go bellow this your metabolism will slow, your car will be slow and won't burn fuel efficiently.

Great post. However, I'm going to quibble about this part. There is no magic number where if you eat more, your metabolism doesn't slow and if you eat less, it does. Your metabolism slows whenever you go into long-term calorie deprivation. Sure, the less of a calorie deficit you have, the less your metabolism slows and the shorter the duration of your deficit, the less it slows. But there isn't a hard line. It's a gradual process of slowing down more and more.

I think this is important to note because a lot of people think that their metabolism isn't slowing down when it is and then they don't understand why they aren't losing weight at the rate MFP (or other formulas) say they should be.

Plus, if you understand that your body is trying to slow down your energy burn rate, you can do things to combat it. Knowledge is power. :happy:

TXBlockhead

bump.

iAlly

Great post. However, I'm going to quibble about this part. There is no magic number where if you eat more, your metabolism doesn't slow and if you eat less, it does. Your metabolism slows whenever you go into long-term calorie deprivation. Sure, the less of a calorie deficit you have, the less your metabolism slows and the shorter the duration of your deficit, the less it slows. But there isn't a hard line. It's a gradual process of slowing down more and more.

Quibble accepted. 1200 and 1500 are only guide numbers and your are right there is no magic line that you cross.