Friday, 12 December 2014

The good, the bad, and the sugary (Part 2 on Diet)

Roses are red, Violets are blue.
Are sugars sweet and unhealthy for you?

This week we talk briefly on the new enemy in modern diets – the carbohydrate, known to you and me as sugar. Once upon a time, fats (particularly the saturated kind found in foods derived from animals) were the worst thing that you could eat. They were linked to heart disease and obesity in a somewhat flawed study in the 1950s which influenced the Western perception on diet. As low-fat foods became popular, however, sugar levels climbed ever higher to make the same foods more palatable. But the problem of heart disease and obesity is worse than ever and now the World Health Organization (WHO) is cracking down on sugar bigtime.

A sugar by any other name…

[caption id="attachment_97" align="alignleft" width="222"](It's sugar.) The white stuff! (CC2.0)[/caption]

Sugar is a carbohydrate molecule – an arrangement of Carbon, Hydrogen, and Oxygen atoms – that our bodies break down in our cells to release the sweet, sweet energy within. Sugar is the building block of the fuels we burn to keep going, and can exist in single molecules (monosaccharides), dual molecules (disaccharides), and more (complex carbohydrates). Each are found in the foods we eat, with varying nutritional implications and as many schools of thought on their importance.

If we imagine each of our cells as being miniature furnaces, then monosaccharides are like wood chippings on the fire – they burn fast for a quick burst of energy. Our bodies burn three types of monosaccharide: the well-known glucose, close second fructose, and galactose. These three monosaccharides are readily absorbed by our bloodstream.

Glucose and fructose are metabolised (burned) straight away for the energy, or are converted to glycogen and stored in our muscles. Galactose is converted into glucose first, but is then treated the same. If our glycogen stores are full and we don’t need energy right that instant (likely because we’re sitting on our behinds watching Doctor Who on Netflix), then the monosaccharides are converted to fat by the liver and stored in fat cells.

A sugar is a sugar is a sugar…

Monosaccharides are sugars which are simple carbohydrates. What of the complex? Let’s start with the disaccharides; two monosaccharides that have combined into one new sugar molecule like a sickly sweet Voltron. The more common varieties on your food packs include sucrose (table sugar), lactose (in your milk), and maltose (the barley/beer sugar).

The sucrose you add to your tea/coffee/branflakes in the morning is made up of glucose and a fructose bound together. Your garden variety lactose is found in milk, also added to your tea/coffee/branflakes (see how easy it is to accumulate sugar in your diet now?). Lactose is a glucose and a galactose molecule. Inability to break apart the bonds holding these two together leads to a condition called lactose intolerance. Finally, we have maltose, two glucoses bound hand-in-hand.

Disaccharides are not dissimilar to monosaccharides – they broken up quickly and burn fast. Both are added to foods, especially those low in fat, for their sweet taste and because they’re addictive. A 2007 study in France found that rats, given a choice between water sweetened with saccharin and water laced with cocaine, chose sweetness over the addictive drug – implying sugary sweetness may be a more powerful an addiction (in rats, at least).

Slow burning sugars

Carbohydrates, besides mono and disaccharides, come in a complex form: that is, more than two monosaccharides get together and form a big molecule. Examples of this are starch and fibre. Starch is just a whole bunch of glucose bound together in a glycosidic bond. It is typically created by plants as a means of storing glucose for energy use later – we have fat cells, plants have starch.

If monosaccharides were fast-burning wood-chippings, then starch is good old fashioned slow-burning log. Starch takes a while to burn through and is far better for sugar processing enzymes, like insulin, to control that energy inferno than simple sugars with burn hard and fast.

Fibre, on the other hand, is made out of indigestible sugars (indigestible for humans, at least). This plays an important role in our digestive system nonetheless, as some of our internal bacteria may feed on it and produce nutrients for us in return, as well as just keeping things moving along nicely. It also plays a role in regulating the absorption of nutrients, like sugars and fats, and in processing cholesterol. Not everything we eat needs to add to us, sometimes it’s about the taking away.

Burn, baby, burn

So there you have it, carbohydrates are sugars that give us energy – or make us fat, depending on how much (or how little) energy you spend in a day. Sugar has come under fire in recent years because of the sheer levels of it in foods. Cola, low-fat yoghurts, even supposedly healthy ready-made soups have exceptionally high levels of sugar added to them, according to the World Health Organization.

WHO is currently working on a draft guideline on the amount of sugar adults and children should consume and currently recommends that it should not exceed six teaspoons. How many teaspoons are in a can of cola? About ten. There is an entire teaspoon of sugar in one tablespoon of ketchup. Surely sugar levels in food will go the way of salt levels in the next decade or so – way, way down. I taste sweet revolution, ladies and gentlemen. Or maybe that’s just my soup.

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