Snapshot series: 3 - The carbohydrates

Carbohydrates are one of the main components of the diet (the macronutrients) and provide the major substrate for energy metabolism within the brain, kidney medulla and red blood cells. 

      Carbohydrates are also important for muscle function in highintensity exercise. Whilst dietary carbohydrates can range from molecules such as glucose and fructose (the simple sugars), through the disaccharides (sucrose, maltose, lactose) to the complex polymers of glucose found in starch, all dietary forms are digested within the intestine so that the simple sugars are the molecules  that are absorbed into the body.

      Dietary recommendations for healthy people suggest carbohydrates should provide between 45 and 60% of dietary energy, depending on age, physical activity and body weight. 

     High intakes of the simple sugars, sucrose or maltose, and even rapidly digested refined grains, are associated with risks to health, including tooth decay and unintentional overconsumption of energy (leading to weight gain). 

  A healthy diet should have most carbohydrate in the complex form, particularly when contained in high-fibre wholegrain cereals and vegetables.

 The idea that carbohydrate is somehow toxic and that low-carbohydrate diets should be eaten by all  is backed up by only few uncontrolled research.