The Chemistry of Weight Loss #2: Our body’s fuel system

Yesterday we looked at the chemistry of fat. Elsewhere, we have looked at the chemistry of carbohydrates

So which one does our body use?

Our body is a complex reactor which is capable of converting  fuel into energy. rather like our car. If we want our car to run, we have to put the right fuel in.  If we have apetrol car  and we put diesel in, for example,  it won’t run.

In just the  same way,  how body has a fuel system . Now it’s not quiet  as simple as that ,as our body  actually has several fuel  systems ,but there is one major  system that  dominates all others  that will look  at  today.  Essentially, our  body runs on  glycogen .

Glycogen is the  simplest  carbohydrate , and is what any complex carbohydrate must be broken  down  into  in order to act as a fuel . As I have discussed elsewhere,  if the glycogen is coming from  complex carbohydrates, then  this is a simple  process,  as simple as breaking a Lego  structure  into individual blocks. This process  can happen quickly  and it is the fuel that  our body uses most of the time,  particularly when doing anything at  all energetic.

Under sustained periods of exercise ,if how  body runs out of  complex carbohydrate,  it runs out of glycogen ,and this process is called going  “to the wall “. This is something experienced by marathon on runners for example.  And it’s the kind of thing  you experience if you skip  breakfast and lead a  busy morning.  By the time lunch rolls round,  you are very lethargic.

So the  lesson is,  that most of the time we are running on  glycogen.

This means that if we run out  of complex carbohydrate , our body must manufacture glycogen from somewhere else , and this is where it becomes complex,  and also represents ana opportunity for  weight loss.


The Chemistry of Weight Loss #1: The chemistry of fat.

We’re a nation of fatties – well at least that’s the popular view. Weight loss programs are scattered across the internet, TV, and (women’s) magazines.

So who do you believe? Which programs and/or diets work, and why?

Well, it’s not too hard to understand, if we go back to basics and look at the chemical reactions that occur in our body, what fat is, how it is made, and how it is removed. Like most things in life, there is a chemical explanation.

The first point to understand is that your body is an incredibly sophisticated chemical reactor that is able to convert very different chemicals into each other, with an efficiency and specificity that would be impossible in any laboratory. No industrial process in even the most sophisticated pharmacalogical facility in the world would be capable of carrying out the sophisticated and complex chemical reactions that our body does every day, silent and unseen.

Lets start by looking at the chemistry of fat. Essentially any animal or vegetable fat is a triglyceride, which is basically shaped like an E:

Three fatty acid chains are connected to a glycerol backbone, hence the name. Note that the 3 fatty acid chains are all straight, with the carbon atoms linked by single bonds. We call this a saturated fat because you can’t fit any more hydrogens on it.

Contrast that structure with this:

The third fatty acid chain has a double bond (in green). This molecule is no longer saturated, as there is room for two more hydrogens. That is, two hydrogens could be added across this bond, to convert it to a single bond and make it look like the molecule in the upper image. So because it is not saturated, we say it is unsaturated. Specifically, it is monounsaturated, as there is one double bond.

If there is more than one double bond, it is said to be polyunsaturated.

Now, you will note that the carbon chain with the double bond is bent. The implications of this is that the molecules will not stack together very well on top of each other, in just the same way that regular shaped boxes will stack together easier than irregular shaped boxes.

This means that monounsaturated triglycerides are generally liquid (like olive oil) and saturated fats (like lard) are solid at room temperature.

Stay tuned

Are White Sugar and White Rice Bleached?

I was asked a very interesting question today – are white sugar and white rice white because they have been chemically bleached?

it’s a good question – if chlorine bleach had been used in anything you ate it would obviously be a cause of concern.

And there have been cases of this kind of thing in the past. It used to be the case that decaffeinated coffee was decaffeinated with dichloromethane, a carcinogenic chemical that you certainly don’t want to be ingesting. At that time there was only one brand that was doing it a different way – HAG.

HAG coffee used supercritical carbon dioxide to decaffeinated their coffee. this was a more expensive process, the much safer as the CO2 quickly evaporated. So be other brands abandoned the dichloromethane and now also use supercritical CO2.

Back to sugar and rice.

As it happens, neither of these products have been bleached. The explanation for the white colour is simply the extra processing.

For sugar, all the brown stuff in brown sugar is impurities that are removed as part of the refining process. In other words, white is the natural colour of sugar crystals (sucrose). So it hasn’t been bleached – it has just been further purified.

And with rice, a similar situation is the case. If you take brown rice and polish it further, you eventually get back to white rice. In other words, brown rice is simply white rice with extra coatings on top. Once these coatings are polished away as part of the refining process, they become white.

Eo there you go – white rice and white sugar are perfectly safe to use. even if they may not be perfectly safe for your waistline.

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.