The glycaemic index tells you how abruptly the carbohydrate in the food you eat is released into your blood as glucose. When glucose appears in your blood your body produces insulin to mop it up: the more glucose, the more insulin. That insulin then stays in your blood trying to process glucose for about two hours, so if the original glucose levels aren't maintained for this time then the insulin demands more glucose to process, making you feel hungry. The glycaemic index can thus help prevent overeating as it tells you which foods (high GI) cause a short-lived spike of high blood glucose which is rapidly absorbed, leaving you feeling hungry, and which foods (low GI) release small amounts of glucose over a long period of time, preventing inappropriate hunger.
In order to lower the GI of your diet you should aim for one low GI food as part of every snack or meal you eat, although it is fine to then eat additional foods of medium or high GI. Things like meat, fish, eggs and most vegetables are GI 'neutral' (neither low nor high) as they don't have much carbohydrate in them so they don't get converted to glucose. The glycaemic index only applies to carbohydrate rich foods, i.e.:
* BreadUnfortunately, it can be hard to tell which of these carbohydrate-rich foods are low and which are high GI as the rating depends on such hard-to-detect factors as whether the starch in the food is bound up with protein or not. In general, however, whole grains are low GI whereas processed grains tend to be high, so bulgur wheat is low but whole wheat crispbreads are high. In addition, all legumes and low-fat dairy products are low, as are sour-dough breads, pasta and noodles (when not overcooked) and pita bread.
* Cereal grains (rice, wheat (flour), barley, etc.)
* Starchy vegetables (e.g. potatoes, peas, corn)
* Legumes (beans, lentils, chickpeas, etc.)
* Fruit (including dried fruit and fruit juices)
* Milk and yoghurt
The following table should help you to identify low GI foods. When a food that you usually eat is in the right-hand column you will hopefully find something on the left, or even in the middle, that you could replace it with.
| low GI (under 55) | medium GI | high GI (over 70) | |
| bread | sour-dough, pita pumpernickel, soy-lin bread, spicy fruit bread, 100% stone-ground grain bread, multigrain bread, most Burgen® and Vogels® breads. | hamburger buns, rye bread, croissant, light rye bread, crumpets, wholemeal bread | white bread, bagels, blackbread, gluten free bread |
| breakfast cereal | All Bran®, porridge, Special K®, rice bran | oatbran, untoasted muesli, Just Right®, Nutri Grain®, Sustain®, Weet-Bix® | Sultana Bran®, Bran Flakes®, Coco Pops® puffed wheat, rice bubbles, cornflakes |
| grains | barley, pasta (all types), noodles, bulgur wheat, semolina | basmati rice, wild rice, Sunrice Doongara® rice, couscous, cornmeal, tapioca | brown rice, long grain white rice, calrose rice, jasmine rice, sushi rice |
| legumes | all beans (baked beans, kidney beans, soy beans, etc.) peas (including split peas) and lentils | broad beans | |
| starchy vegetables | taro | new potatoes | kumara, potatoes, parsnips, french fries |
| dairy products | milk, low fat yoghurt, custard, low fat ice cream | regular full-fat ice cream | |
| biscuits/snacks | oatmeal biscuits, ANZAC biscuits, bhuja mix, nuts, banana cake, chocolate cake | most biscuits including digestives, milk arrowroot and shortbread, potato chips, corn chips, most muffins, popcorn | cupcakes, lamingtons, water crackers, crispbread, rollups, fruit bars |
| fruit | cherries, grapefruit, peach, dried apricots, apple, pear, plums, orange, grapes, kiwi fruit, banana | sultanas, apricots, mango, paw paw, raisins, rockmelon, pineapple | watermelon, dates |
It's also important to realise that simply eating low GI food doesn't make your diet healthy. Some low GI foods can be very fatty, as fat slows the rate of emptying of your stomach and hence how quickly the food gets to the intestine where it is converted to glucose, so you still need to limit serving sizes of these foods to stay healthy.
Researchers at Sydney University who have promoted low GI diets recommend that in addition to at least four servings per day of low GI carbohydrates everyone should eat:
* Two servings per day of low fat dairy products. These keep your bones healthy (particularly important if you spend a lot of time lying down) and also encourage weight loss;They also recommend limiting saturated fats in your diet. All animal fats are saturated but all plant oils except palm and coconut oil are poly or monounsaturated and hence good for lowering cholesterol.
* Five servings per day of vegetables and two of fruit (seems like heaps of vegetables to me but I make up containers of salad once or twice a week to help me to achieve this without continually eating carrots!);
* At least two servings per week of oily fish (sardines, salmon, mackerel or tuna). This gives you the omega-3 fatty acids that keep your heart healthy;
* One or two servings per week of nuts and seeds. You could achieve this by snacking on nuts or by eating bread with seeds in it, sprinkling sesame seeds on steamed vegetables, adding nuts to a salad or eating peanut butter. Nuts give you the poly- and monounsaturated fats that help lower cholesterol;
* Eight glasses per day of fluid, not counting caffeine-rich drinks like coffee or colas.
Finally I have also made a point of eating a protein-rich food every time I eat (which is five times a day) as I find that this helps with my concentration and general physical function. In addition, protein increases your metabolism for about two hours after you have eaten it, again helping you to control your weight.
Taking all these points into consideration I have designed for myself a daily eating plan which I have found easy to stick to as it keeps away debilitating hunger and doesn't involve counting calories. In accordance with the recommendations of the Sydney University people, if at a given meal I have eaten all the recommended foods and am still hungry then I am free to eat whatever else I want, but this doesn't happen very often. I am hoping to move to in the future to just eating the foods on the plan, staying a little bit hungry, and seeing if that causes me to actually lose weight.
In order to stick to my plan without having to think about it too much I keep the following things in stock most of the time:
* legume spreads. You can buy hummus or red bean paste (a sweetish spread sold in Chinese stores), or you can make your own by pureeing cooked legumes and mixing them with a little oil or yoghurt and then herbs, tomato paste, onion, lemon juice etc. for flavour. I divide these into containers with enough for a week in each then store them in the freezer until needed. They are good as spreads or as dips for raw vegetables;Recipes and menu ideas for low GI diets are available in a series of books called "The Glucose Revolution", "The New Glucose Revolution", "The Low GI Life Plan" etc. that should be available in your local library. I have found these helpful for snackfood ideas although for mains I tend to eat as I did before, simply moving to eating pasta, quinoa or basmati rice where I would previously have eaten potatoes or a higher GI rice.
* protein-rich cuppa soups;
* low GI bread and biscuits or muffins;
* low-fat yoghurt and cottage cheese;
* containers with pre-measured servings of snacks and salads. (This way I can divide something larger like a fruit crumble into a number of easy snacks, which saves thinking at snack time.);
* vegetables that require minimal preparation such as celery sticks or carrots.
Heather
May 2007