The Glycaemic Index
Carbohydrates break down to glucose at different rates. This is referred to as the Glycaemic Index, or G.I., in which carbohydrates are given a rating between 0-100
Low to medium G.I. carbohydrates (G.I. of 0-70)
Low to medium G.I. carbohydrates break down slowly during digestion, releasing glucose more gradually into the bloodstream and thus maintaining a much more stable level of blood glucose. The lower the G.I., the slower the rate of digestion and therefore, the more gradual the supply of energy to the muscles.
If your carbohydrate intake is predominantly made up of low-medium G.I. foods, you will find that you will not get hungry to quickly and your energy levels will be more sustained. You will have more stamina and training will become easier. A low to medium meal at least 2-3 hours before a workout will delay fatigue, as energy will be transported to the muscles more gradually.
Low to medium G.I. foods include porridge, sugar-free muesli, oat cereals, wholemeal bread, pulses and beans, basmati rice, brown rice, rice noodles, risotto rice, pasta, most fruit and vegetables, nuts and seeds.
High G.I. carbohydrates (G.I. of 70+)
High G.I. carbohydrates break down quickly during digestion and are absorbed rapidly into the bloodstream, resulting in a surge of blood glucose. A high G.I. drink or snack just before or during sport gives your muscles a quick energy boost. Likewise, the body resynthesises glycogen at a faster rate immediately after exercise, so consuming high G.I. carbohydrates straight after endurance will increase the rate at which our muscles can recover and gives us the stamina to continue training.
If you regularly eat large amounts of high G.I. foods, you body will produce too much insulin which will cause hunger pangs and energy slumps, so you should try to limit your intake of high G.I. carbs to immediately before, during and after exercise and concentrate on basing your regular diet on low-to medium G.I. carbohydrates.
High G.I. carbohydrates include processed cereals, white rice (pudding rice, short grain rice), white bread, potatoes