University College Hospital What is the Glycaemic Index? Children and Young People s Diabetes Service The glycaemic index (GI) is a guide to how quickly or slowly carbohydrate foods affect blood glucose levels. Foods with a high GI value are digested (broken down) quickly to produce glucose and foods with a low GI value are digested (broken down) slowly to produce glucose. How is the Glycaemic Index worked out? The GI of a food is calculated by looking at what happens to the blood glucose level of volunteers after eating a test portion of a food. A graph of the rise and fall in blood glucose level is used to calculate the GI value. University of Sydney www.glycemicindex.com
The GI of a food is influenced by more than just sugar. GI is related to the chemical structure of the foods. Other factors that affect the glycaemic index include: Fat and protein - the presence of fat (fried foods, oil, butter, cream, cheese) and protein (meat, fish, eggs) in a food will slow down the rate of digestion meaning the glucose is released more slowly into the bloodstream. Fat may also increase resistance to insulin. Fibre foods that contain soluble fibre e.g. oats, fruits, vegetables, beans, pulses are digested and released more slowly resulting in a slower rise in your blood glucose levels. Type of starch different types of starch have different chemical structures and are therefore digested and absorbed at different speeds. This is why pasta has a lower GI compared to rice. Processing for example, easy cook rice has a higher GI than basmati rice and whole jumbo oats has a lower GI than rolled oats. Different brands of the same cereal, such as cornflakes, can have different GI s due to different processing methods. Cooking methods for example, a mashed potato has a higher GI than a boiled new potato or chips due to the level of processing (and addition of extra fat) Ripeness for example, a riper banana will have a higher GI than an unripe banana as the starch naturally breaks down into sugars and is digested and absorbed more quickly. What do the GI values mean? A low GI food has a value of 55 or below compared to a high GI food which has a value of 70 or more. Why use glycaemic index? Choosing lower GI foods can improve blood glucose levels and reduce the risk of both high and low blood glucose levels after meals. Choosing lower fat low GI foods is associated with better overall blood glucose management and can lower HbA1c. The GI can also help you to choose the right food at the right time, if you want to treat a low blood glucose level or push the blood glucose up during exercise choose high GI foods; if you want to prevent low blood glucose levels at night choose lower GI foods.
Glycaemic Index Tables Glycaemic Index Breads, biscuits & crackers Low GI (GI = less than 55) Multigrain bread, rye bread, fruit bread, sourdough, soy & linseed bread, multigrain breads, chapatti, corn tortilla Medium GI (GI = 56-70) Roti, pitta bread, crumpet, croissants, oat cakes, rich tea, digestives, shortbread High GI (GI = more than 70) White bread, whole meal bread, bagel, baguette, rice cakes, water crackers, puffed crisp bread, pop tarts Pasta and Grains Cereals Fruits and fruit juices Barley, pasta e.g., Tagliatelle, Spaghetti, rice noodles, noodles, basmati rice. Rolled oat porridge, All Bran, Frosties Apple, orange, banana, mango, dates, peaches, Brown rice, couscous, Weetabix, millet porridge, Muesli Fruit and Fibre Pineapple, White rice, easy cook rice, instant rice, tapioca Cornflakes, Branflakes, Cheerios, Coco pops, instant oat porridge, rice porridge, rice krispies Watermelon, Cranberry juice Potatoes/Roots/Tubers Yam Chips, baked potato, sweet potato, new potato Boiled potatoes, instant mashed potato, mashed potatoes (without added fat and milk) Vegetables and Pulses Sweetcorn, peas, carrots, plantain, taro, chickpeas, kidney beans, lentils, soybeans Desserts & Confectionary Strawberry jam, chocolate, ice cream Pumpkin Popcorn, potato crisps, full fat ice cream Sugars Fructose, Lactose Sucrose (table sugar), honey Swede Doughnuts, pancakes, jelly beans, skittles, real fruit bars Glucose, glucose tablets
Glycaemic Index Drinks Low GI (GI = less than 55) Apple juice, orange juice, pineapple juice Medium GI (GI = 56-70) Cola, fizzy orange drinks, Seven Up, Ribena High GI (GI = more than 70) Isotonic Sports drinks, sparkling glucose drinks, Lucozade Milk & Dairy Whole milk, low fat milk, milk shakes, yogurts and Fromage Frais, fruit smoothies Soya yogurt, sweetened condensed milk Rice Milk How to use the glycaemic index Swapping to eating more medium and low GI foods will help blood glucose management. This does not mean avoiding high GI foods adding a low GI food or a protein food to a high GI food will slow down how quickly the blood glucose levels rise after eating. Here are some ideas to lower the GI of the diet Breakfasts Swap to lower GI cereals porridge, oat based cereals. Eat fruit and yogurt in place of cereal. Swap white and wholemeal bread for wholegrain or sourdough breads. Try fruit breads toasted Add fruit to breakfast cereal Mash avocado on wholegrain toast Add egg, baked beans or peanut butter to toast Mix yogurt with fruit to make a breakfast smoothie Lunches Use pitta bread, wraps and flat breads in place of white and wholemeal bread. You can also replace bread with oat and wholegrain crackers Use multigrain or wholegrain bread and rolls for sandwiches. Try rice and pasta salads made with low fat sauces as an alternative to sandwiches Make homemade cereal bars that use fruit, seeds and oats in place of bought snack bars in lunch boxes Include fruit packs and vegetable sticks as extras in lunch boxes Main Meals Swap potato for sweet potato and new potato Use pasta and rice or noodles in place of potato Include 2-3 servings of vegetables with meals. Mash vegetables into potato Add beans and pulses to stews/casseroles, you can replace some of the meat with beans and pulses.
Snacks Try and keep snacks small but if you need to fill up go as low fat as possible. Remember high fat increases insulin doses. All types of fruit are great, try making fruit skewers baked or grilled for a change Mix fruit and yogurt together for a healthy filling snack. Have veg sticks and low fat dips like hummus Supper Before bed only snack if you really need the extra food. Low fat milk, yogurt and yogurt drinks make good bedtime drinks Wholegrain crackers or oatcakes with low fat cream cheese Breakfast cereal with low fat milk Contact Details: You can contact the Childrens Diabetes Dietitians on childrensdiabetesdietitians@uclh.nhs.uk Expert advice and information about children and young people's type 1 diabetes can be found at www.uclh.nhs.uk/t1 If you need a large print, audio or translated copy of this document, please contact us on 020 344 79364. First published: May 2017 Date last reviewed: May 2017 Date next review due: May 2019 Leaflet code: UCLH/SH/PAED/CYPDS/GI/1 University College London Hospitals NHS Foundation Trust