Fitness

Low GI Diet


Posted by Simon on 31 October 2007 18:17:34

If you've tried fad diets in the past only to discover they are impossible to stick to and leave you feeling hungry and irritable, then it's time to start eating sensibly; enter the 'Low GI Diet'.

G.I. stands for Glycaemic Index and is a measure of how quickly a food is broken down in the body to release glucose into the bloodstream. Foods with a low glycaemic index break down and release glucose slowly into the blood. Foods that have a high glycaemic index break down and release glucose more quickly.

As the name suggests, the low glycaemic index diet is based around eating foods that have a low glycaemic index, and cutting down on foods with a high GI.

Why is the Glycaemic Index important?

When you eat foods that have a high glycaemic index, they release glucose into your bloodstream very quickly. The body tries to keep the amount of glucose in the bloodstream pretty constant so it needs to get rid of this 'spike' of energy and the way it does this is to release the hormone insulin into the blood. Insulin tells the body to store energy as glycogen in the liver and muscle cells, and as triglycerides in fat cells. In other words you store some of the energy as fat to get rid of the excess energy. Wave goodbye to that six-pack!

If this isn't bad enough, high GI foods give you a quick fix of energy, but they can't sustain it. Once that sugary snack has released its short energy spurt into your system and your body has mopped it all up, you'll feel lacking in energy and hungry - wanting another snack.

Low GI foods release energy slowly for a prolonged period of time, so you don't get an energy spike followed by a crash, and your body doesn't need to produce so much insulin to store the excess. The effect: less tendency to store body fat and less snacking.

What is the glycaemic index of different foods?

The table below shows the GI of some different foods. Notice that some foods that are high in sugar actually have a low GI. Milk chocolate, for example, has a high sugar content but it's also high in fat. Fat slows down the digestion of food, lowering the GI. However it is important to note the glycaemic index of your diet is not the only factor to control the body's tendency to store fat; the total amount of energy in your diet is also very important - and fat contains approximately three times more energy gram for gram than protein or carbohydrate. So don't think you'll get fit on a diet composed of chocolate bars and crisps just because the GI is low!

Classification Glycaemic Index Some examples
Low GI 55 and under Roasted and salted peanuts, most fruit and vegetables (except potatoes), whole milk, whole grains, Special K, wholemeal bread, pasta, basmati rice, wholegrain porridge, milk chocolate, crisps.
Medium GI 56 - 69 Sucrose, croissant, some brown rices, boiled potatoes, raisins & sultanas, wholemeal bread, Weetabix, Shredded Wheat, Ryvita, couscous, digestive biscuit, pitta bread.
High GI 70 or more Corn Flakes, baked potato, mashed potato, white rice, white bread, water melon, swede, rice cakes, boiled parsnips.

Balanced diet

The important thing with any diet is to make sure it is balanced. It is no good eating a low GI diet if you're not getting all the nutrients your body needs to stay healthy. A balanced diet should consist of something from each of the five main food groups. These are:

  • bread, cereal (including breakfast cereals) and potatoes (starchy foods)
  • fruit (including fresh fruit juice) and vegetables
  • meat and fish
  • milk and dairy foods
  • fat and sugar
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