What is the Glycaemic Index : University College London Hospitals NHS Foundation Trust

The Glycaemic Index (GI) is a guide to how quickly or slowly carbohydrate foods affect the rise in blood glucose levels.

Foods with a high GI value are digested (broken down) quickly, and foods with a low GI value are digested (broken down) slowly to produce glucose.

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 level

The GI of a food is influenced by more than just it’s sugar content. 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 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 e.g. pasta has a lower GI compared to rice.
Processing –processing by the food industry can alter the GI of a food; easy cook rice has a higher GI than basmati rice and whole jumbo oats have a lower GI than rolled oats. Different brands of the same cereal, such as cornflakes, can have different GIs.
Cooking methods – 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 – 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.

GI values go from 0 to 100.

low GI foods have a value of 55 or below
high GI foods which have a value of 70 or more.

Choosing lower GI foods can improve glucose control and reduce the risk of both high and low glucose levels after meals. Choosing low fat, low GI foods is associated with better overall diabetes 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 glucose level or push the glucose up during exercise choose high GI foods, if you want to prevent spikes in glucose levels after eating, choose lower GI foods.

Glycaemic Index	Low GI (GI = less than 55)	Medium GI (GI = 56-70)	High GI (GI = more than 70)
Breads, biscuits & crackers	Multigrain bread, rye bread, fruit bread, sourdough, soy & linseed bread, multigrain breads, chapatti, corn tortilla	Roti, pitta bread, crumpet, croissants, oat cakes, rich tea, digestives, shortbread	White bread, whole meal bread, bagel, baguette, rice cakes, water crackers, puffed crisp bread, pop tarts
Pasta and Grains	Barley, pasta e.g., Tagliatelle, Spaghetti, rice noodles, noodles, basmati rice	Brown rice, couscous	White rice, easy cook rice, instant rice, tapioca
Cereals	Rolled oat porridge, All Bran, Frosties	Weetabix, millet porridge, Muesli Fruit and Fibre	Cornflakes, Branflakes, Cheerios, Coco pops, instant oat porridge, rice porridge, rice krispies
Fruits and fruit juices	Apple, orange, banana, mango, dates, peaches	Pineapple	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	Pumpkin	Swede
Desserts & Confectionary	Strawberry jam, chocolate, ice cream	Popcorn, potato crisps, full fat ice cream	Doughnuts, pancakes, jelly beans, skittles, real fruit bars
Sugars	Fructose, Lactose	Sucrose (table sugar), honey	Glucose, glucose tablets
Drinks	Apple juice, orange juice, pineapple juice	Cola, fizzy orange drinks, Seven Up®, Ribena®	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

Breakfast

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, 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