Food and Weight Loss #5

So how do you stop your body going into starvation mode and piling on fat?

The answer is simple – don’t starve yourself.  You do not have too go hungry to lose weight.

The biggest breakthrough in the area of dietary intake in recent years has been the advent of the glycaemic index.  Essentially, it measures how quickly a particular food is converted to glucose.  As we have seen, your body can only tolerate a certain range of blood glucose levels.  If it’s too low, you run out of energy, and if it is too high, your bloods injects insulin, which converts your glucose to fat.

This is the reason why so many overweight people are diabetics.  They have been eating so much sugary food that’s their pancreas (the organ at produces the insulin) gets worn out.  That is, it has been so bombarded with simple sugars, it is simply worn out from all the insulin it has had to produce.

So toss out your calorie counter, and get a list of foods and their glycaemic indices.

If you eat food that has a low glycaemic index, which are usually complex carbohydrates, your body will break down the carbohydrates as required to produce the glucose.  So this stops you putting on weight.

But how do you lose weight that you might already have?

Well, if you are eating well, lots of filling vegetables, meat, and complex carbohydrates, your body will feel no need to store fat, and so will attempt to shed the fat that it has.

The only issue here is that the energy contained in fat, since it is more condensed, is not so easily acquired as the energy in carbohydrates.  In other words, fat cannot be metabolised as quickly as carbohydrates.

So all you need to do is choose an activity that doesn’t require quick energy – something like walking.

If you are walking, your body has time to break down the fat to produce the required energy, and there is absolutely no exercise anywhere that is as good for fat loss alone as walking.

So there you go – don’t starve yourself, eat food that is low in glycaemic index, and walk a lot, and the fat will just melt away.

Food and Weight Loss #4

Both complex carbohydrates and fat may be converted to energy. If we are going to lose weight, we really mean we want to lose fat, so the real question is – how do we make sure that we convert fat to energy, instead of converting carbohydrates to energy?

One obvious answer, and one that has been behind every failed diet that people have ever been on, is to say “don’t eat any carbohydrate.”

And at first glance this seems to make sense, which is why this approach has been so popular for so long. Obviously if I take away one source of energy – carbohydrate – my body will use the only source left – fat.

The problem with this approach is that your body is an exceedingly complex chemical reactor with billions of chemical reactions going on every second – and the notion of energy in – energy out is far too simplistic.

In real terms, if you cut down your intake of carbohydrates, the body goes into starvation mode.  That is, it battens down the hatches, and says “it looks like food may be in short supply – I better preserve what reserves I have.”

To do this it does two things.  Firstly, it slows your metabolism.  This means that it slows the rate at which it uses energy.  This is of course is the very last thing you want.  The other thing it does is to convert what fuel it does have to the most efficient form for storage, which is fat.

Why is fat more efficient for the storage of energy?

Let’s look at their chemistry and we’ll see why:

Let’s look at the formula of say stearic acid (a fat): C18H36O2

A similar sized carbohydrate (about the same weight) would be C8H16O8

Do you see the difference? The fat is made up almost entirely of carbon and hydrogen, whereas the carbohydrate has much of its weight taken up by oxygen.

Your body, since it is now completely taken up with efficiency of storage says “I don’t need the oxygen – I can get it from air later on.”

So since the fat stores more carbon for a given weight than the carbohydrate,  that’s what you all body does with the food it gets.

So limiting food intake may mean you lose weight, but it’s mostly water.  Your percentage of body fat actually has increased.  And what happens is that when you get down to your desired weight, and start to eat “normally” again, your body now says “at last, some food – quick – store it away as fat before the supply dries up again.”

This is why people who diet often fluctuate and experience the horror of seeing weight go back on that they have just taken off.

So how do you avoid that happening? Stay tuned.

Food and Weight Loss #3

Many things are complex carbohydrates. Paper and wood for example, but you can’t eat them?

In terms of food, complex carbohydrates are generally starchy in nature, and there is no greater battleground than breakfasts cereals.  Let’s compare the information panels of two supposedly healthy breakfast cereals and see what they tell us – Weet-Bix and Vita Brits.

Weet-Bix is 67% carbohydrate with 3.3% sugar.  Vita Brits is also 67% carbohydrate but only 0.4% sugar.

Products with sugar this low are very rare.  Unfortunately our palate is used to sweet things and likes sugar in most things.

Stated simply, the Vita Brits is the best source of complex carbohydrate I have come across, although Weet-Bix is also pretty good.

So what’s so important about complex carbohydrates anyway.?

Well, we’ve seen that how our body runs on glycogen as fuel.  As it happens, there is only a certain level of glycogen that they body can tolerate.  If it gets below this, you essentially run out of fuel – a phenomenon that athletes (marathon runners in particular) refer to as “hitting the wall.”  – Where you lose all your energy, and even standing up and moving a few paces is an enormous chore.

If your blood glycogen gets too high, however, that can also cause problems, and so your body will have to remove glycogen.

It does this by supplying insulin, which essentially converts the glycogen to fat.

Now if glycogen can be converted to fat, then it makes sense to see that fat can be converted to glycogen.

So there are two potential sources of fuel (fat and complex carbohydrates).  If we have sufficient complex carbohydrates on board, our glycogen levels never get too high, and the body simply breaks down the complex carbohydrates as required, and fat doesn’t enter into the picture.

So in an ideal world we’d all eat food which was low in sugar and high in complex carbohydrates.

But in the real world that doesn’t happen of course – we eat too much sugar, it gets converted to fat, and we put on weight.

So how do we get rid of the fat, and cause it to be broken down?

More tomorrow.

 

Carbohydrates and Sulphuric Acid (or How to Dehydrate Carbohydrates)

One of the more spectacular chemical demonstrations getting around is sulphuric added to sugar.

What on earth happened? Suddenly out of the pristine white sugar we see a hideous black hissing column rising, like something out of a horror movie.

Well, as it happens, sulphuric acid is very dry.  It may seem and odd thing to say about a liquid, but concentrated sulphuric acid is only about 2% water.  It is a thick (kind of like runny honey) clear, odourless liquid.  If you get it on your skin it burns like hell, but the reason is not quite what you think.

All it’s doing is reacting with the water in your skin.  Because it is so dry, it gets very excited when it encounters some water and this makes it very hot.  As a matter of fact when handling sulphuric acid, students are often taught a rhyme:

May her rest be long and placid
she added the water to the acid
completely forgot what we had taught her
you should add the acid to the water

the reason for this is that if you add water to sulphuric acid it will generate so much heat so quickly it will explode in your face.  Even if you do it the right way – adding the acid to the water – the water will quickly boil.

I once had a corn on my little toe that I wanted to get rid of, as it was really annoying me.  I figured the best way to get it off would be to burn it off with sulphuric acid.  So I very carefully placed a drop of it onto the corn and was ready to wash it off as soon as it had burned through the corn.

But nothing happened – the drop just sat there.  I even tried some chromic acid on it (a souped up version of sulphuric acid) but it didn’t do anything either.

The reason is simply was that the corn was very dry skin and there was nothing for the sulphuric acid to react with.

Now you will recall that carbohydrates are just carbon and water.  Because sulphuric acid is so dry, and craves water so much, it will actually reach into the molecular structure and rip the waters off the carbons.

So what you see happening in the video is the sulphuric acid is ripping the water off the carbons, therefore leaving just the black carbon behind.  Because this generates so much energy, the water turns to steam.  This steam bubbles up through the carbon giving it a porous, honeycomb type structure, which increases the volume greatly.  Therefore you see the column rising out of the glass.

For the same reason if you spill even dilute sulphuric acid onto cotton clothing it will rip through it in an instant.   Anybody who has spilled battery acid onto their clothes will know that.  That’s why acid resistant safety gear is made out of synthetic fibres.

Carbohydrates and Ironing Aids

What is in ironing aids and how do they work?

Ironing aids (such as Fabulon) have four components:

1.  Water.  This provides a steam cushion as the hot iron glides over it.

2.  Gliding agent.  This is typically a silicon oil that is colourless and odourless and provides a lubrication for the iron as it glides across the fabric

3.  Fragrance.

4.  Starch (either natural or synthetic).  Starch of course is the component that stiffens the fabric when it is ironed. But it’s not the actual starch that stiffens the clothes. If you just sprayed some starch on your clothes and let it dry, it wouldn’t make a scrap of difference to the stiffness of the fabric.

What is needed to stiffen the fabric is starch plus heat.  This produces a process called hydrolysis which is essentially where the starch molecule is broken into bits and water is added across the bonds at which the molecule is severed.

These bits of starch are simply short chain carbohydrates and they are termed dextrins.  Dextrins have a number of properties in the food and pharmaceutical industries, and one of them is the stiffening of clothes.  This occurs as the dextrin binds to the fabric (particularly cotton) and helps straight and out the physical structure of the weave.

Interestingly, dextrins are also the stiffening agents in the crust of a nice crispy bread.