What’s the GI of meat, chicken, fish, eggs and cheese? I can’t find these foods in the GI database.
The GI is a measure of carbohydrate quality. Meat, eggs, fish and cheese are protein foods so they don’t have a GI because they have either no carbs, or so little the GI can’t be measured.
Eaten alone protein foods like these have very little effect on your blood glucose levels. It’s carbohydrates that are mainly responsible for the rise and fall in blood glucose after meals. Foods that are high in carbs include:
- Cereal grains (rice, wheat, oats, barley and rye and anything made from them like bread, breakfast cereals, pasta and noodles)
- Starchy vegetables like potatoes, taro, yams, sweet corn and sweet potatoes. Most green or salad vegetables have so little carbohydrate we can’t measure the GI
- Legumes (pulses) including beans, chickpeas, lentils and split peas
- Fruit such as apples, pears, peaches, oranges, strawberries, mangoes, bananas and melons
- Dairy foods like milk, ice cream and yoghurt (but not cheese which is a protein food, or butter or cream which are mostly fat)
I have heard that pasta made of strong wheat flour (such as durum) has a lower GI than pasta made of softer wheat flour. Is this true?
We asked Prof. Jennie Brand-Miller to answer this. She says: ‘My understanding is that durum wheat is a very hard wheat and that makes it ideal for pasta manufacture. It gives the pasta its lovely golden colour because the aleurone layer is included with the endosperm fraction. Hardness and strength are two different things. Hardness refers to how the grain cracks up in the milling process, while strength refers to its protein content. Many Australian wheats, for example, are both hard and strong at the same time, making them highly desirable for many applications, especially bread making.’
She goes on to say, ‘I have seen data showing that pasta made from any old wheat has a relatively low GI. It’s the low degree of gelatinisation (low moisture dough) that makes it low GI. The high protein content might help a little but it’s not the major factor. If you make bread from durum wheat, it will have a high GI because bread making allows for full gelatinisation. If you overcook pasta (perhaps canning too), then it will become more highly gelatinised and that will increase its GI. For the most part, properly cooked pasta (al dente) has a GI of 40–50.’
I’ve been following The Low GI Diet and have noticed some recipes include the use of filo pastry. Does filo pastry have a low GI? I love spinach pastries and even vegetable pies, but I am wondering if pastries have a high GI value?
Pastry by itself hasn’t been GI tested. It’s not something you normally eat as a meal. But the real problem with most shortcrust and flaky pastry products is that they tend to be very high in fat, particularly saturated fat (remember the ingredients for making pastry are essentially flour and butter with a little water plus sugar for a sweet pastry). The reason we include occasional recipes with filo pastry is that you can get that lovely crisp in the mouth pastry feel with a lot less fatty pastry. Just 2 or 3 sheets of filo lightly sprayed with olive oil (not melted butter) will do the job. So a spinach triangle or a vegetable pie made with filo can provide a nourishing and tasty meal and help you achieve those five serves of veggies a day – providing you make sure it’s got lots of veggie filling and just a little filo pastry! Catherine Saxelby’s Fresh Plum and Ricotta Strudel made with a few sheets of filo shows you how you can up your fruit intake with a delicious low fat, low GI dessert. You’ll find the recipe in our January 2006 GI Newsletter.
Photo: Ian Hofstetter, The Low GI Diet Cookbook
I have read in some GI lists that fresh coconut is low GI, is this true? Coconut does not seem to be on your list!
Coconut is a nut (not a fruit) and it has not been GI tested. It contains very little carbohydrate per serving (just 1 g in a 15 g portion) and it is virtually impossible to GI test. But it is high in fat (5 g in a 15 g portion) and the fat it contains is nearly 90 per cent saturated. So use very small amounts of coconut products such as coconut milk or desiccated coconut in your cooking.
Look it up in our A–Z: The GI Glossary continued
Atherosclerosis or hardening of the arteries is a slow progressive disease and can go virtually unnoticed until it produces problems such as angina or a heart attack. Most heart disease, whatever form it takes, is caused by atherosclerosis—clogging on the inside wall of the arteries through the slow build up of fatty deposits (called plaques) which narrows the arteries and reduces the blood flow. This is not just a ‘plumbing’ problem, but one in which inflammation plays a key role. Atherosclerosis can affect the arteries elsewhere in the body including the brain, kidneys, and the arms and legs. When the arteries to the heart are affected and blood flow is reduced, the heart muscle doesn’t get enough oxygen for pumping blood, and eventually this causes central chest pain (angina pectoris). Elsewhere in the body when blood flow is restricted by atherosclerosis there’s a similar effect: in the legs, it can cause muscle pains on exertion; in the brain, it can lead to a variety of problems from ‘funny turns’ to strokes. An even more serious consequence of is when a thrombosis (blood clot) forms over a patch of atherosclerosis on an artery. This process can occur anywhere in the arterial system and lead to a complete blockage of the artery. The consequences can range from a small heart attack to sudden death.
Beta cells The cells in the pancreas that produce insulin. They are found grouped together in the Islets of Langerhans.
Blood pressure The pressure of the blood on the walls of the blood vessels caused by the beating of the heart. Every body has blood pressure, although not everyone’s blood pressure is high. Hypertension is defined as having blood pressure above 140/90 mm HG. An abnormal blood pressure is considered to be 120/80.
Carbohydrate, a vital source of energy found in all plants, is the starchy part of foods like rice, bread, legumes, potatoes, and pasta and the sugars in foods like fruit, milk and honey. Cheap, plentiful and sustainable, it is the most widely consumed substance in the world after water and the basis for a healthy diet. Some foods contain a large amount of carbohydrate (such as cereals, potatoes, and legumes) while other foods such as carrots, broccoli and salad vegetables are very dilute sources. The simplest form of carbohydrate is glucose, which is a universal fuel for our body cells, the only fuel source for our brain, red blood cells and a growing foetus, and the main source of energy for our muscles during strenuous exercise.
Cholesterol is a soft, waxy substance found in the blood and in all the body’s cells. It’s an important part of a healthy body because it is part of the walls around all of our cells, and is a major component of many of the hormones our body’s produce. Most of the cholesterol in our body does not come from the foods we eat, but is in fact manufactured by the liver. High levels of cholesterol in the blood may lead to blocked arteries, heart attack and stroke. Cholesterol and other fats can’t dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are several kinds, but the most common ones are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
Coeliac disease is a condition where the lining of the small intestine is damaged due to an immune reaction from your own body to a small protein known as gluten. Gluten is found in certain grain foods like wheat, rye, triticale and barley, and in much smaller amounts in oats (as a contaminant). The only treatment for coeliac disease at present is a gluten-free diet.
Type 1 diabetes is characterised by high blood glucose levels due to the body’s complete inability to produce insulin. It occurs when the body’s immune system attacks the insulin-producing Beta cells in the pancreas and destroys them. The pancreas then produces very little or no insulin. Type 1 diabetes occurs most often in young people but can develop in adults.
Type 2 diabetes is characterised by high blood glucose levels caused by an insufficiency of insulin and the body’s inability to use insulin efficiently. It is thought to occur when the body becomes resistant to insulin. The pancreas compensates initially by producing more insulin, then eventually becomes exhausted and produces insufficient insulin. Type 2 diabetes occurs most often in middle-aged and older people but is being seen increasingly in younger adults and teenagers.
Gestational diabetes can occur during pregnancy, but usually goes away after the baby is born. Hormones released by the placenta during pregnancy reduce the effectiveness of the mother’s insulin. It is usually managed successfully with healthy eating and regular physical activity, but in some cases extra insulin is needed.
Dyslipidaemia abnormal levels or composition of the blood fats known as cholesterol and triglycerides.
Fat provides lots of kilojoules/calories – more than protein or carbs per gram – so you only need a small amount each day. The message today is know your fats. Focus on the good ones (mono- and poly-unsaturated fats) and give the bad fats (trans fats and saturated fats) the flick.
Saturated fats are solid at room temperature. These are the fats on meat or chicken skin, and in butter, cheese, palm oil and coconut oil. We don’t actually need to eat any saturated fat, since the body can make all it requires, but it is fairly difficult not to eat some, since all fats are actually mixtures of saturated and unsaturated fats.
Unsaturated fat is liquid at room temperature. These good mono- and polyunsaturated fats provide you with essential fatty acids that form your cell membranes; help you absorb the fat-soluble vitamins A, D, E and K; form part of your body’s hormones; provide insulation; and help you absorb some anti-oxidants from fruit and vegetables.
Trans-fats are produced during manufacture and behave like saturated fat in a product (increasing its firmness), as well as in our bodies (increasing the risk of heart attack). Foods high in trans fats include fried fast foods, some margarines, crackers, cookies and snack – so read the label before you buy these foods.
Fatty liver is the build up of excessive amounts of triglycerides and other fats inside liver cells; also known as steatohepatitis or NASH (Non-Alcoholic Steato-Hepatitis).
Fibre Dietary fibre only comes from plant foods – the outer bran layers of grains (corn, oats, wheat and rice and in foods containing these grains), fruit and vegetables and nuts and legumes (dried beans, peas and lentils). We need about 30 grams of fibre a day for bowel health and to keep regular. There are two types of fibre—soluble and insoluble—and there is a difference.
Soluble fibres are the gel, gum and often jelly-like components of apples, oats and legumes. By slowing down the time it takes for food to pass through the stomach and small intestine, soluble fibre can lower the glycemic response to a food. Good sources include: oatmeal, oat bran, nuts and seeds, legumes (beans, peas and lentils), apples, pears, strawberries and blueberries.
Insoluble fibres are dry and bran-like and commonly called roughage. All cereal grains and products that retain the outer coat of the grain they are made from are sources of insoluble fibre, eg wholemeal bread and All-Bran®, but not all foods containing insoluble fibre are low GI. Insoluble fibres will only lower the GI of a food when they exist in their original, intact form, for example in whole grains of wheat. Here they act as a physical barrier, delaying access of digestive enzymes and water to the starch within the cereal grain. Good sources include: wholegrains, wholewheat breads, barley, couscous, brown rice, bulghur, wheat bran, seeds, and most vegetables.
Fructose or fruit sugar is an alternative sweetener that is nearly twice as sweet as table sugar but provides the same amount of kilojoules. As the name suggests, it is found naturally in most fruits.
To be continued next month.