Glycaemic Index & A Healthy Weight
What is Glycaemic Index (GI)?
Most carbohydrates foods are digested to produce glucose but they do so at different rates, some slowly and some quickly. The glycaemic index (GI) is a ranking of carbohydrate foods according to their effect on blood sugar levels. It was originally designed to help people with diabetes to make better food choices but research has found that it might be useful in helping people to get to and stay at a healthy weight.
Carbohydrate foods are the body’s main energy source. Most carbohydrates are broken down in the gut and released as glucose (sugar) into the blood stream. Foods containing carbohydrates include: breads, cereals, rice, pasta, noodles, fruit, vegetables, sugar, honey, biscuits, cakes etc.
How does GI help with weight?
High blood sugar from high GI foods causes increases in the amount of insulin your body makes. Insulin helps to lower blood sugar levels after a meal but it also is important in helping your body to store other nutrients including fat. High levels of insulin encourage your body to store fat, rather than burn it. This means that when blood sugar increases it can encourage your body to store fat.
If you eat high GI foods, your blood sugar will be higher, followed by higher insulin levels and more fat storage. When you eat low GI foods your blood sugar level stays lower (but not too low) and so insulin stays lower and this can encourage your body to burn fat. Low GI foods are also more satisfying and help keep your metabolism running faster. This is why they are important for helping anyone to lose weight or to keep off weight they have already lost.
Which foods are low and which are high GI?
Only foods with carbohydrate can raise blood sugar levels. Any foods with no carbohydrate are low GI foods. Foods with no carbohydrate include meat, chicken, fish and eggs. Foods that have carbohydrate can be divided into low or high GI foods although there can be variations between the GI of a food depending on the way it is cooked or the particular variety or the season.
High GI foods
- Most breads (brown or white)
- Potatoes (mashed and baked)
- Rice (white)
- Cooked fruit
- Some root vegetables e.g. parsnips
- Foods high in sugar e.g. soft drinks, sweets, biscuits, cakes
- Cereal bars
- Ketchup
Low GI foods
- Porridge or high fibre cereals
- Pasta (dried or fresh, wholemeal)
- Noodles
- Milk (use skimmed or low fat)
- Brown rice and Basmati rice
- Fresh fruit
- Most vegetables and salads
- Pulses – beans, peas and lentils
- Meat, poultry, fish and eggs