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Carbohydrates are found in fruit, vegetables, milk, grains and legumes
Foods high in carbohydrates are an important part of a healthy diet. Just as petrol is fuel for a car, carbohydrates are the main fuel for our body.
Carbohydrate is the key nutrient that provides us with energy (kilojoules), protein and fat are the others. Sugars, starches and dietary fibre are all types of carbohydrate. All carbohydrates (except some fibre) are digested to form blood glucose - which is converted to energy to support physical activity, the brain, nervous system, heart and kidneys and help burn fat efficiently.When people eat a food containing carbohydrates, the digestive system breaks down the digestible ones into sugar, which enters the blood.
- As blood glucose levels rise, the pancreas produces insulin, a hormone that prompts cells to absorb blood glucose for energy or storage.
- As cells absorb blood glucose, levels in the bloodstream begin to fall.
- When this happens, the pancreas start making glucagon, a hormone that signals the liver to start releasing stored sugar.
- This interplay of insulin and glucagon ensure that cells throughout the body, and especially in the brain, have a steady supply of blood glucose. Harvard Nutrition Source
Carbohydrate quality is important; some types of carbohydrate-rich foods are better than others:
- The healthiest sources of carbohydrates are unprocessed or minimally processed whole grains, vegetables, whole fruits, beans, low fat milk and yoghurt - they promote good health by delivering vitamins, minerals and fibre.
- Unhealthier sources of carbohydrates include white bread, pastries, soft-drinks, juice, added sugar and highly processed or refined foods. These items are often high in energy and contain little nutritional value. When eaten in excess they may contribute to weight gain, and promote diabetes and heart disease.
While included in the grouping of protein nutrients, milk, yoghurt and most types of cheese do contain fats and carbohydrates as a sugar called lactose. Many yoghurts also have sugar, honey or fruit added to make the product more appealing.
Carbohydrates and managing diabetes
Types of carbohydratesSimple carbohydrates contain one or two sugar molecules and are naturally found in such foods as fruits (glucose, fructose) and milk (glucose, galactose).
Added sugars in foods and drinks are also simple carbohydrates and are used for example in soft drinks, biscuits and desserts. Sucrose or table sugar (glucose, fructose), brown sugar, raw sugar, molasses and honey are examples of added sugars. These are the foods that need to be kept to a minimum, they give us kilojoules but have none or little of the nutrients the body needs.
Complex carbohydrates are made up of three or more sugar molecules and are found in grains, legumes and some vegetables. Bread, cereal, rice, beans, kumara, taro, green bananas, potatoes and pasta are some examples. These foods can be refined, such as white flour and rice, or unrefined, such as whole wheat, brown rice and whole potatoes.
Whole grain or unrefined choices are a best bet for nutrition and fibre!
Carbohydrate Fact #1
Carbohydrate Fact #2
Starch in grains, vegetables and legumesStarches and sugars raise blood glucose levels and when there are disproportionate levels in the diet, can contribute to weight gain.
Grains (wheat, rice, barley, oats), potatoes, corn and beans are all starchy foods.
When grains are made into white bread, processed cereal, crackers, biscuits, cookies, cakes, piecrust, and anything else made with highly processed flour it has the effect of doing some of the work of our digestive systems before the food even goes into our mouths.
If grains or legumes remain ‘whole’ and less processed, such as beans, brown rice or whole barley, the starch is broken down into sugars much more slowly.
Different kinds of starch have different arrangements of molecules, and some are easier for our digestive enzymes than others. One kind of starch, called amylose, is broken down quite slowly. The higher the amount of amylose in a starch, the more slowly it is digested. Different types of rice have differing percentages of amylose. Long grain rice such as basmati rice, where grains tend to stay more separate, are higher in amylose. Shorter grain rice such as jasmine, tend to produce creamier and stickier rice, are low in amylose.
One processed food that seems to be digested more slowly than anticipated is pasta, where the starch molecules are so tightly packed that only about half is rapidly digested when the pasta is cooked "al dente" (slightly firm). Cooking time and thickness of the pasta greatly affects glycaemic level produced. See glycaemic index
Carbohydrates (or “carbs”) are your body’s main fuel. So you should have some at every meal to give you energy.
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Image credit Appetite For Good LLC
Unlike leafy green vegetables some vegetables have high levels of starch and need to be counted as carbohydrates when choosing healthy eating patterns and planning meals.
High-carb vegetables (starchy vegetables)
Starchy vegetables include:
Potatoes, parsnips, kumara, taro, yams, cassava, plantains and breadfruit.
- Taro roots have more energy than potatoes - 100g provides 470 kilojoules (112 calories). Their energy value chiefly comes from complex carbohydrates in them. Nonetheless, the roots are very low in fats and protein than cereals and pulses.
- Taro root does contain dietary fibre - 100g flesh provides approx 4.1g
How much should you eat a day?
On a healthy eating plate, high-carb vegetables are within the ¼ of the plate allocated to carbohydrates.
Low carb vegetablesLow-carbohydrate vegetables include tomatoes, silverbeet, broccoli, cauliflower, carrots and lettuce. We need to eat a variety of colours and types daily and over a week.
Low-carb vegetables are a great source of fibre, vitamins and minerals. Go for a variety of colours every day — dark green, yellow, orange and red.
If you can’t get them fresh, frozen is fine.
How much should you eat a day?
Try to eat at least 3 – 4 handfuls of low-carb veggies a day. For dinner that’s half a plate of vegetables or salad. Aim for variety in types of vegetables and colours.
Have plenty of variety of types and colours, that’s key.
Image credit Zeynel Cebeci
Fruit are essential ingredients for a balanced healthy diet. Most of us do not eat enough fruit and vegetables on a daily basis to capture the health benefits. Choose whole fruit where possible it provides a good source of dietary fibre.
Fructose is the main sugar present in fruit and vegetables and affects blood glucose. Eating too much fruit at one time will raise blood glucose levels.
Fructose in whole fruit and vegetables usually has a lower glycaemic index than table sugar and usually a lower effect on blood glucose. But – different varieties of fruit have varying levels of fructose depending on ripeness and source, with tropical fruits usually higher than apples, for example.
Fructose is often added to packaged products as a sweetener – check the label.
Compared to soft-drinks, sports drinks and energy drinks, juices are a fairly nutritious choice. While all can contain sugars in comparable amounts, no-added-sugar juices get their sweetness from naturally fructose, whereas most sugar-sweetened drinks get their sweetness from a variety of added sugars. Packaged drinks labeled ‘Fruit Drink’ usually have less or no juice. Check the label on packaged drinks.
|Orange juice||120 cal / 520 kJ||28 g||22 g||0.5 g|
|Orange||60 cal / 251 kJ||15 g||12 g||3 g|
|Apple juice||120 cal / 520 kJ||28 g||24 g||0.2 g|
|Apple (with skin)||100 cal / 418 kJ||25 g||19 g||4 g|
1 glass (250 ml) estimates only
It’s good to eat a variety of fruit.
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Wheat, oats and rice are the grains most commonly eaten in Australia and New Zealand, with others such as rye, barley, corn, triticale, millet and sorghum making a smaller contribution.
There are a number of different types of grains found within the true cereal grains which are from the botanical family ‘Poaceae’ including –
Wheat including spelt, faro, bulgur
The ‘pseudo-cereal’ group are not part of the Poaceae botanical family, in which ‘true’ grains belong, however they are nutritionally similar and used in similar ways to ‘true’ grains.
These include –
These are not actually grains but are in fact seeds from a number of different plant species external to the Poaceae family. As such, they are not by definition ‘true’ grains, yet they are considered ‘pseudo-cereals’ since their overall nutrient composition is similar and they are prepared and used in similar ways to ‘true’ grains. Pseudo-cereals are increasingly being used in the manufacture of niche breads, flatbreads, crispbreads, pasta, breakfast cereals and snack bars as well as on their own as alternatives to rice, pasta and cous cous. Australia Grains and Legumes Council
Although the structures of the various cereal grains are different, there are some common features they all share, including the following layers:
Wholegrain carbohydrates, such as rolled oats, brown rice and wholemeal flour, contain more fibre and are digested more slowly than refined grains, which helps people with diabetes to maintain stable blood glucose levels and feel fuller for longer.
A high fibre diet helps to lower cholesterol levels. People who currently have a low fibre diet should increase their fibre gradually and drink plenty of water to prevent constipation. It is good to have some carbohydrate foods at each meal, but large portions can make blood glucose levels rise and over time may also contribute to excess weight gain.
How much to eat
Keep carbohydrate foods to a quarter (¼) of the plate, or a ‘fist size’ serving.
Rice has been part of the human diet for thousands of years. Historical evidence suggests that rice may have been produced and consumed up to 10,000 years ago. This, alongside its current global status as the world's most important human food, makes rice production responsible for feeding more people over a longer period than any other crop.
Rice is a source of protein and contains various vitamins, such as thiamin and niacin, and minerals, such as zinc and phosphorus. Some nutrients, including vitamin E, magnesium, potassium, and manganese, are lost during milling and polishing — the process by which brown rice becomes white or polished rice — and are therefore only found in brown rice.
Some specialty types of rice, such as those that are purple or red in color, contain more of the pigment anthocyanin.
Despite these nutrients, when eaten on its own, rice (whether white or brown) from existing varieties does not provide enough micronutrients for optimum health.
Rice and glycaemic index
In the past, rice had been generically assessed as a high-glycaemic index (GI) food. GI is a measure of the relative ability of carbohydrates in food to raise blood glucose levels after eating. High-GI foods can increase a person's chances of getting diabetes, while low-GI foods can help lower the chances of developing diabetes.
Different types of rice have different GIs, ranging from a low of 48 to a high of 92, with an average medium GI of 64. This indicates that rice can be part of a healthy diet for the average consumer and that people who have diabetes or are at risk of developing it can select the right kind of rice to help keep a healthy low-GI. International Rice Research Institute (IRRI)Image credit Mars Inc, Uncle Ben brand
Not a true rice, wild rice is the grain of an aquatic grass native to North America. Today most of what is sold as "wild" rice is actually cultivated and then mechanically harvested and processed. Wild rice is sold with the bran on the kernel (like brown rice) giving it a black appearance.
Brown rice has the outer hull removed, but still retains the bran layers which are rich in minerals and vitamins, especially the B-complex group, It is a 100% whole grain food and takes about 40 to 45 minutes to cook. Because of the oil in the bran layer, brown rice has a limited shelf life of approximately six months.
Parboiled rice (also called converted rice)
The rice is treated at the harvesting stage while still in the hulls. It is soaked and steamed, before being dried. This process alters the nature of the starch, resulting in transparent grains that will be less sticky and more separate when cooked. Parboiled rice, however, is not actually ‘cooked’ during the process. It also allows some nutrients to transfer from the hull into the grain, giving a more nutritious product than untreated rice.
Enriched white rice has the outer husk removed and the layer of bran milled away until the grain is white. Is it enriched with thiamin, niacin and iron and fortified with folic acid to restore nutrients lost during processing.
Instant rice is cooked in hot water, just as rice is prepared at home and in restaurant kitchens, then dehydrated. The instant rice is then ‘cooked’ simply by rehydrating the rice for several minutes, and is then ready to serve.
Both white rice and brown rice can be precooked and can be featured as ‘instant rice’ products. Since the nutritional quality of the instant rice that emerges out of the cooking process depends on the nutritional quality of the rice going into that cooking process, instant brown rice is a better choice than instant white rice.
Lab tests have found that there was no appreciable difference in the nutrient profiles of regular versus quick-cooking. In addition, unlike instant vs. slow-cooked oatmeal, instant brown rice in some cases had an equivalent or even a lower glycaemic index (raises blood glucose more slowly) than longer-cooking rice. Lower glycemic index diets have been linked to a reduced risk of heart disease, diabetes and age-related macular degeneration, a leading cause of blindness.
Servings of rice
Just watch your serving size, as brown rice is still somewhat carbohydrate-dense, so the overall impact on blood glucose and total caloric intake is still significant if you consume too much.
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WORLD HEALTH ORGANISATION (WHO) MARCH 2015 GENEVA - A new WHO guideline recommends adults and children reduce their daily intake of free sugars to less than 10% of their total energy intake. A further reduction to below 5% or roughly 25 grams (6 teaspoons) per day would provide additional health benefits.
Free sugars refer to monosaccharides (such as glucose, fructose) and disaccharides (such as sucrose or table sugar) added to foods and drinks by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.
“We have solid evidence that keeping intake of free sugars to less than 10% of total energy intake reduces the risk of overweight, obesity and tooth decay,” says Dr Francesco Branca, Director of WHO’s Department of Nutrition for Health and Development.
The WHO guideline does not refer to the sugars in fresh fruits and vegetables, and sugars naturally present in milk
Much of the sugars consumed today are “hidden” in processed foods that are not usually seen as sweets. For example, 1 tablespoon of tomato sauce contains around 4 grams (around 1 teaspoon) of free sugars. A single can of sugar-sweetened soda contains up to 40 grams (around 10 teaspoons) of free sugars. World Health Organisation Guideline: Sugars intake for adults and children
1 teaspoon sugar = 4 grams of carbohydratePlease note: Honey has the same effect on blood glucose as sugar.
Fizzy soft drinks are a prime source of extra energy (kilojoules) that can contribute to rises in blood glucose levels and weight gain and provide no nutritional benefits. Studies indicate that liquid carbohydrates such as sugar-sweetened drinks are less filling than the solid forms causing people to continue to feel hungry after drinking them despite their high energy value.
Sugar and Cereals and other foods
Choosing whole, unprocessed breakfast cereals – such as a bowl of porridge, muesli or whole wheat breakfast biscuits – that don’t have lengthy ingredient lists is a great way to avoid eating added sugars. Unfortunately, many common breakfast foods such as ready-to-eat breakfast cereals, cereal bars, breakfast drinks and pastries can contain high amounts of added sugars.
Some simple information from BBC Science, March 2014
Eating too much sugar can lead to unhealthy eating patterns. Sugar can be a mood-booster as it prompts the body to release the 'happy hormone' serotonin into the blood stream.
However, the pleasant sugar rush triggers an increase in insulin as the body strives to bring blood glucose levels back to normal. This has the knock-on effect of causing a 'sugar crash' and makes many crave yet more sugar, which can lead to a cycle of binge-eating.
Added to this, our bodies aren't able to tell when we've had enough of certain types of sugar. Researchers have found that food and drinks sweetened with the simple sugar fructose do not trigger the same sense of fullness as other foods with similar calories.
A study from Yale University found that while glucose suppressed the parts of the brain that make us want to eat; fructose did not. The test participants also reported feeling more satisfied after consuming glucose compared to fructose. Taken together these two aspects increase the risk of overeating. Many processed foods are excessively sweetened by sucrose, which contains 50% fructose.
Manufacturers often add extra sugar to food because it makes them taste better. When fat is removed from a processed meal, for example, sugar is often added to help disguise the blander taste. Because of this, many foods we think of as wholesome - like yoghurt, muesli bars, low-fat snacks and fruit-flavoured water - may actually contain much more sugar than we realise.
Like salt, these so called 'added sugars' also help extend the shelf life of some foods, such as bread, breakfast cereals and tinned fruit and vegetables.
If we consume more sugar than we burn through activity our liver converts the excess glucose into fat. Some of this fat stays in the liver but the rest is stored in fatty tissues around the body.
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