On April 21/2011 the following article appeared in the “REAL LIFE” section of the Calgary Herald.
The article - “Are You Confused About Carbohydrates” – contained several statements that are just not true or are misleading. The errors in this article were serious enough for me to write a letter to the editor (which naturally did not get published) in an effort to tell the truth. Letters to the editor are limited to 250 words and I needed more space in an effort to set the record straight.
Here is my point by point analysis. Article statements appear first, in bold followed by the truth.
1. “Carbs are an essential nutrient” – this is not true. There is no published DRI for carbs. The Inuit people lived very well without carbs.
2. “The Brain runs exclusively on carbs”. This is true but the body has 3 built in mechanisms for turning fat and protein into carbohydrate. a) ketone bodies from dietary intake and from fat storage, b) glycerol released from fat breakdown, and c) protein breakdown known as “gluconeogenesis” .
3. “You can think of carbs as single, double and longer chains of sugar”. The first comment is ‘so what’? The second part of the response is that all carbohydrates are digested into single molecule sugars, mainly glucose. We only absorb single molecules sugars known as “monosaccharides” . We do not absorb disaccharides nor polysaccharides. So it doesn’t matter how complex the carbohydrate is, when digested it turns into a monosaccharide. The only advantage of a complex carbohydrate is the reduced rate of digestion and therefore the reduced speed of blood glucose elevation (the sugar spike as some call it).
4. “You need carbs to fuel muscles” . The fact is muscles operate very well on fat as a source of energy. During mild to moderate exercise 50-70% of energy is derived from fat (based on Respiratory exchange ratio data). The native Inuit diet was 85% fat. You only require carbs for high intensity, short term exercise.
5. “Carbohydrates store water—so it is not uncommon for low-carb dieters to lose 5 to 15 pounds of water weight when restricting carbs”. This is half true. Every gram of carbohydrate stored in the muscle and liver as glycogen will demand 3 grams of water. However, at top levels of carb storage – in the range of 600 grams—you would only be storing 1800 grams (4 pounds) of water. To lose all 4 pounds you would have to be totally depleted of carbohydrates in storage. That will not happen.
It is true that The Institute of Medicine (IOM) along with Dieticians of Canada regularly recommend the minimum level of carbohydrate intake at 130 gm per day. However, on the same page of the 2002 IOM report, it is acknowledged that the brain will be fine without carbohydrates because it works fine on ketones, glycerol and protein- derived glucose.
6. “You need a variety of carbs for health.” The “nutritional density” of most natural protein foods is higher than most carb based foods. The only nutrients that are in question are Vitamin C (not in animal protein foods) and Fibre – also not in animal food sources (this one does open some questions – again look at he native Inuit diet and tell me about their fibre sources .)
Lastly, the rationale that carbs are “comfort” food with the implication that “therefore they are needed”, is false prophecy. For many people beer, scotch, wine and recreational drugs are comfort food—does that mean we need them?
My conclusion based on evidence and science is that carbohydrates are not essential !!!