Nutrition 2c: carbohydrates

As part of my personal training course, I took a module in nutrition.

This series is about the various topics that we covered on that course and discusses the areas where I agreed and where I disagreed with the course notes.

***

My course notes

• Functions of carbohydrate: my course notes make the following points:
  • Carbohydrate is used by the body for energy
  • The brain can only function on glucose
  • Muscles need carbohydrate for energy when the intensity is high
  • Carbohydrates contain fibre, which is good for efficient gut function
• Recommended daily intake of carbohydrates: my course notes explain that:
  • According to the World Health Organisation, the Amercian College of Sports Medicine and the Department of Health, our current carbohydrate intake is too low and should be higher, at least 55 – 60% of daily calorific intake
• Types of carbohydrate: there are two types of carbohydrate, simple and complex.  Simple carbohydrates include monosaccarides such as glucose, fructose (fruit sugar) and galactose (a component of milk sugar) and disaccharides such as sucrose (table sugar), maltose (starch sugar) and lactose (milk sugar).  Complex carbohydrates are found in starchy foods, such as wheat, potatoes and rice.
• Type of fibre: Fibre is the cell walls of plant cells.  There are two types of fibre, soluble and insoluble:
  • Soluble fibre is digested in the small intestine but insoluble fibre is not.  Soluble fibre enters the blood and has been found to help lower blood cholesterol and lower the risk of cardiovascular disease.
  • Insoluble fibre passes through the small intestine into the large intestine and gives the gut something to work against.  Insoluble fibre can be problematic in excess as it decreases transit times through the gut and may limit absorption time for essential nutrients.  Also, some forms of insoluble fibre bind to minerals including calcium and zinc and prevent their absorption.
• Health risks of a high carbohydrate diet:
  • Apparently, there are no known clinical conditions caused by an overconsumption of complex carbohydrates.
  • An excessive consumption of simple carbohydrates can cause type two diabetes and tooth decay.
• Health risks of a low carbohydrate diet:
  • Fibre deficiency
  • Vitamin and mineral deficiency
  • Antioxidant deficiency
  • Expensive

***

My thoughts

I have a couple of my key thoughts on carbohydrates, which I will summarise here before going into some research:

• There is no such thing as an essential carbohydrate.  Unless you are doing heavy anaerobic exercise or weight-training, if you never ate another carbohydrate again, you’d be fine.  All those fear-inducing statements about “the brain needing glucose” are irrelevant because the body can make all the glucose it needs from other macronutrients.
• If you are doing heavy anaerobic exercise or weight-training, you probably don’t need as much carbohydrate as you think you do.  For an example of what is possible, read Matt Lalonde’s post at Robb Wolf’s site.  Matt was doing the main workout on the CrossFit site as recommended and has a 405lbs squat at 170lbs bodyweight so he’s not a slouch.  For a round-up of some of the most intelligent people in fitness writing about low-carb diets and weight-training, check out the T-Nation low-carb roundtable parts one and two.
• If you want to lose fat then most people will find that they need to avoid eating very many carbohydrates.  As Charles Poliquin notes, if you want to lose fat quickly then you probably need to eliminate grains and fruit and make sure that most of your carbohydrates come from fibrous vegetables.
• The above statements probably apply to the majority of people (Charles Poliquin says he uses a low-carb protocol with 75% of clients) but some people are just different and do better on more carbohydrates.
• The statement “there are no known clinical conditions caused by an overconsumption of complex carbohydrates” is so untrue I still don’t quite believe that they wrote it.  I’ve put together a short section on research articles below that they must have completely ignored to be able to publish this.
• If you want to get really big, really fast then ignore all of this and just go and eat as much food as you can, including plenty of carbs.  Just don’t come running to me if you get metabolic syndrome and have to spend your later years in a home…
• The idea that a low-carb diet is fibre deficient, vitamin deficient or antioxidant deficient is completely misleading.   It is possible to eat vegetables until they come out of your ears and you are ten times over the RDA’s for all vitamins, minerals and antioxidants and still eat low-carb.  You don’t get vitamins, minerals and antioxidants from grains and that’s where the carbs come from.  I really hate it when people make irrelevant points and then pretend they’ve won the argument.
• And anyway, if cereals were good for you then why the hell would you need to “fortify them” with vitamins and minerals?

***

Research: carbohydrate intake causes diseases

I was so infuriated by the statement that my course notes made about carbohydrates (“there are no known clinical conditions caused by an overconsumption of complex carbohydrates”) that I went away and pulled up some studies to prove that they are being extraordinary economical with the truth.  Here they are (mostly courtesy of the excellent Healthy Diets and Science blog):

• Prolonged exposure to high glucose concentrations impairs the function of human pancreatic islets, thus causing diabetes (JCI: Prolonged exposure of human pancreatic islets to high glucose concentrations in vitro impairs beta cell function)
• Eating too much fruit can make you insulin resistant, which can lead to metabolic syndrome and ultimately type two diabetes (N&M: Fructose, insulin resistance and metabolic dyslipidemia)
• Overeating carbohydrates has been linked to increasing diabetes but overeating protein and fat has not been similarly connected (AJCM increase consumption of refined carbohydrates and the epidemic of type two diabetes in the USA)
• The rise of carbohydrate consumption correlates very well with the rise of the diseases of civilisation (mainly heart disease and diabetes) (MH: The colonisation of Europe and our Western diseases)
• Excess carbohydrate intake can cause Alzheimer’s (EJIM: Nutrition and Alzheimer’s Disease)
• High intakes of refined carbohydrates and sugar are associated with increased cancer incidence (ICT: Controlling Hyperglycemia)
• High intakes of carbohydrates have been connected with significant (105%) increases in stroke risk for women (AJE: Carbohydrate intake and stroke risk in women)

***

Research: low carb diets help reduce the effects of disease

And following directly on from the idea that excess carbohydrate causes metabolic syndrome (and therefore increases the risk of getting diabetes and other diseases) is the simple idea that if you STOP eating carbohydrates you can help reverse the damage you have done.  Here are some research articles (again, courtesy of the excellent Healthy Diets and Science blog) to support the idea:

• Low-carb diets have been pronounced both safe and effective (JHND: a review of low and reduced carbohydrate diets)
• Low-carb diets help reduce the effects of type two diabetes (BJGP: Low carb diets for diabetes control)
• There is mounting evidence that low carb diets are an effective intervention for patients with type two diabetes (DM: Nutrition in patients with type two diabetes)

***

Research: cereals are worthless and bad for you

And just because the “healthy cereal” industry is probably the second greatest dietary scandal known to man (after the idea that saturated fat causes heart disease), here are some links to show you that cereal is pointless, bad for your health and should be avoided at all costs (links again, courtesy of the excellent Healthy Diets and Science blog):

• Human beings have not adapted to a cereal-based diet and this means they get ill when they eat cereal (BMC: Agrarian diet and diseases of affluence)
• Low protein, starch-based diets have been connected with poor development and lower-limb deformities in young children (BMJ: Exotic diets and the infant)

***

Hopefully, by now, you should be able to see that:

• Eating too many carbs puts you at risk of diabetes
• If you are already on the road to insulin resistance or type two diabetes, then stop eating carbohydrates!
• So-called “healthy” cereals contain no nutrition of any value whatsoever and you’d be better off eating the packet that they come in

Now go eat some eggs instead.