Friday, November 14, 2008

Poor old maligned carbohydrates and a word on SUGAR

I've been reading several posts about how "carbs don't agree with them" and have been chewing on this for quite a few days. In fact, I've been puzzled by the carb conundrum to a big degree especially as carbohydrates play such a pivotal role in the body. If you're an athlete, then carbohydrates become even more important.

For a start, our bodies run on carbohydrate in two different ways - through processes called gluconeogenesis and glucose oxidation (through the Krebs cycle) - anyone at University studying biochemistry would be pretty aware of this. This process is called glycolysis.

Here is the definition below:
Glycolysis is:
  1. An ATP-generating metabolic process that occurs in nearly all living cells in which glucose is converted in a series of steps to pyruvic acid.
  2. The metabolic breakdown of glucose and other sugars that releases energy in the form of ATP.
The metabolic breakdown of glucose and other sugars that releases energy in the form of ATP.The first stage in the production of energy by breakdown of glucose in body cells; a chain of chemical events requiring a specific set of enzymes, and resulting in formation of ATP (adenosine triphosphate). In aerobic metabolism subsequent sequences produce several times more ATP, thereby providing a greater quantity of energy per molecule of glucose, utilizing oxygen, and producing carbon dioxide and water — comparable to burning organic fuels in air. In anaerobic metabolism (metabolism which does not use oxygen) glycolysis is the only means of energy production from glucose, and lactate is the end-product. This occurs in cells which cannot utilize oxygen (red blood cells), predominately in some components of skeletal muscle (fast, ‘white’ fibres), and probably to some extent in all cells when there is a shortage of oxygen. However, it also occurs in the first 1-3 minutes after a sudden increase of demand in cells which will subsequently make all the necessary ATP aerobically, because the glycolytic system can respond within seconds whereas both the biochemical pathways of aerobic metabolism and the systems for supplying them with oxygen take time to adjust; the start of vigorous exercise, even in a trained athlete with large numbers of ‘red’ muscle fibres, is the most obvious example.

We produce energy by converting ADP to ATP. In other words, carbohydrates make us move.

When we cut carbohydrates from our diet, our bodies begin to rely on fat or protein to be chemically converted into carbohydrates for use in our bodies as energy. I can hear some people saying "but that's what I want to do to lose body fat!"

In theory this may be good, but carbohydrates also are intimately tied up with neurotransmitters, for example serotonin, which control brain function. Our brain functions exclusively on glucose. Although we have control of what we consume most of the time, if our brain senses a lack of carbohydrate through a drop in the neurotransmitter serotonin, then it will do almost anything to override our thinking that carbs are evil and we'll basically go for anything that will boost serotonin levels FAST - that is have a giant great big binge on sugary fatty foods. Not unsurprisingly most people I have ever met who espouse a low carb diet have often had trouble with "bingeing and overdoing it" in the past.

In athletes and specific situations, low carb days are not harmful and can have benefits in certain situations, however as an every day thing, they are not conducive to muscle gain, increasing fitness or wellbeing. In my opinion if you want to turn into a bingeing mad monkey go low carb, the longer the better!

Where I think people "go wrong" is in their choice of carbohydrates - put simply, the more refined or processed the carbohydrate source is, the worse the "reaction". This can be tied up with the Glycaemic Index - most highly processed carbs are high GI which cause insulin to spike rapidly and fall just as fast, hence giving you that sugar high/sugar crash that most of us have talked about in the past. In my opinion it's important that 35-50% of intake comes from carbohydrates - a mix of low, medium and high GI carbs and that nutrient timing is looked at. Focus your starchy carbs post workout and then try them at other times of the day as well if you feel you need a bit more. Try less processed grains like quinoa, oats and buckwheat for something a bit different.

What I think people are really trying to say when they say that CARBS ARE EVIL is that sugar and high fructose corn syrup are the work of the devil and I'd have to agree with them. I'm going to add another post to this to stop this from getting too long

1 comment:

Magda said...

Liz, I can totally 110% relate to the "go low carb and turn into a binging monkey" scenario. When prepping for comps last year and having to cut out most carbs other than morning oats and the tiny bit of rice PWO, I was constantly binging. I even went through a phase where I'd make BS a sandwich, cut off the crusts (which he didnt like) and then devour them all with added butter. I was addicted to bread crusts. How sad is that??!! Now I know why!!