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Low carb vs High carb vs no carb…endless debates on how much of carbohydrates is required and humongous amounts of research, each promptly showing contradictory results !

So what do we do, other than to demystify this… here is the first lesson on carbohydrates.

What are carbohydrates ?

Carbohydrates are essentially complex chains of sugar molecules (composed of carbon, hydrogen and oxygen). They come in various forms and the most common ones are sugars, starches and fibers.

Why are they needed by our body ?

Carbohydrates provide the body with the fuel that is needed for functioning. It provides glucose which is the primary source of energy for cells and the only source of energy to the brain.

How are Carbohydrates classified?

The earlier classification of carbohydrates was into simple carbohydrates and complex carbohydrates. Simple carbohydrates are those with either one or two sugar units ( monosaccharides – glucose/ fructose and disaccharides – sucrose/lactose/maltose) whereas those with three or more are complex carbohydrates.

This system of classification assumed that simple carbohydrates are bad and complex carbohydrates are good. However, more recent studies say that it is much more complex than what it seems !

The new system of classification

Glycemic index is the new system that measures how fast and how much blood sugar rises after you consume a food with carbohydrates. Carbohydrates that break down faster during digestion have higher glycemic indices.

Harvard School of Public Health says ” One of the most important factors that determine a food’s glycemic index is how highly processed its carbohydrates are. Processing carbohydrates removes the fiber-rich outer bran and the vitamin- and mineral-rich inner germ, leaving mostly the starchy endosperm.” Essentially this means that the more processed a food is, the higher its GI value.

The other factors which affect the GI value of a food are

fiber – the more fiber, the better it is since fiber slows down the absorption of sugar into the blood stream 

ripeness – ripe fruits and vegetables have more sugar and hence a higher GI 

type of starch – some starch are easily broken into sugar molecules than others- for ex: the starch in potatoes are easily broken down, and hence it has a higher GI

fat content and acid content – the more fat or acid contat, the slower the absorption 

physical form – finely ground grain has a higher GI vs the coarsely ground grain form

Currently the reference food for glycemic index value is glucose, which is assigned a value of 100. Low GI foods have a value of 55 or <55, Medium GI foods have 56-69 and High GI foods have >70

The impact of diets filled with high GI food is quite detrimental. It is linked to a host of diseases like diabetes, heart disease and increased risk of obesity.

The Glycemic Index does not tell us about the amount of carbohydrate in the food- it tells us only the rate at which the sugar is absorbed into the blood stream. To tell us both – the amount of carbohydrate in the food as well as the impact on the blood sugar level, we can use the Glycemic Load. This is got by multiplying the glycemic index with the amount of carbohydrate in the food portion /serving.

Here is how Wiki explains this : ” Glycemic load for a single serving of a food can be calculated as the quantity (in grams) of its carbohydrate content, multiplied by its GI, and divided by 100. For example, a 100g slice serving of Watermelong with a GI of 72 and a carbohydrate content of 5g (it contains a lot of water) makes the calculation 5*0.72=3.6, so the GL is 3.6. A food with a GI of 100 and a carbohydrate content of 10g has a GL of 10 (10*1=10), while a food with 100g carbohydrate and a GI of just 10 also has a GL of 10 (100*0.1=10).”

How much carbohydrates is needed in your diet ?

The FAO and WHO Dietary guidelines recommend 55-75% of the total energy requirements from Carbohydrates but restricting the “free sugar” intake to 10% ( Free sugar is defined as all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices). The Institute of Medicine of the National Academies recommends 130 grams per day, the minimum amount of glucose required by the brain.

However, note that each individual’s requirement will vary depending on his/her specific conditions.

Major Learnings

  • Eat more of whole grains / whole grain products in the place of processed grains
  • Eat more high fiber fruits and vegetables
  • Eat less potatoes !!!

Check the Glycemic Index database here and decide what all you should include and leave out from today 🙂

Reference : documents and articles from Harvard School of Public Health, Wiki, Institute of Medicine, EUFIC, University of Sydney’s Glycemic Index Database

Disclaimer : I am not a nutritionist, neither have I got any formal education on Health, nutrition or food sciences. All I am trying to do here is help myself, and through that help others understand healthy living and its application in our daily diets. I have tried to refer to as many articles and publications from authoritative sources, however every explanation may not be academically accurate always.

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One Comment

  1. eat less potatoes? are you kidding me? i live to eat potatoes. 😀
    ummm…now you know why I wrote that..;-)


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