Carbohydrates are the leading and most preferable energy source for the body. They are unique in how they effectively supply the body with energy. Compared to fats, gram for gram, carbohydrates supply less energy, yet the body prefers and is wired to use energy primarily from carbohydrate sources. That, my friend, is epic. So we just cannot do without them.
We have learnt how carbohydrates are in various forms based on their compositions and properties. You can see it here to learn about that if you haven't.
I am sure it is now safe to agree that you now know that carbohydrates aren't just rice or bread or pasta alone. They are present in potatoes, vegetables, legumes, grains, fruits, nuts and seeds too.
Where are carbohydrates found?
Carbohydrates are found chiefly in plant foods. The best of them are seen in whole plants upon which little or no processing is done. Plant foods in their wholeness have the best of all the properties and benefits of carbohydrates. Whole carbohydrate foods also contain other nutrients that are beneficial to the body for their healing purposes.
Flaxseeds for example are excellent foods that contain lignans which have been found to be anti-carcinogenic. They are also rich sources of dietary fibres and omega-3 fatty acids which also makes them a superfood. All this while also being a carbohydrate source.
Some carbohydrate food nutrients are accessible upon cooking while some micronutrients present in them are denatured in the same process. I always recommend eating fruits and green vegetables in their raw state as often as possible in order to get the maximum phytochemicals (most of which are antioxidants) from them. These phytochemicals can be denatured by heat, and that will cause the carbohydrate food to lose its other nourishing ability. It will be a greater loss if we then discard the water in which it was cooked.
Low to medium heat for leafy vegetables (if you must cook them), and high heat for other starchy vegetables, legumes and grains. Cooking processes like steaming, broiling, baking and roasting, help to preserve the nutrients in them to a large extent even while they are being cooked.
Carbohydrates Vs obesity and diabetes.
Since obesity became an epidemic, there has been a series of approaches that have been followed to try to curb its growth and risk in society. Scientific and unbiased conclusions have been to either maintain or increase carbohydrate consumption in place of fatty foods in those affected, as the case may be. This also will be carefully selected and portion control will be carefully adhered to. This is a sound evidence-based approach.
This is because it has been observed that the amount of energy supplied by fats in fatty foods (9 calories per gram), is greater compared to that of carbohydrates (4 calories per gram). A high-carbohydrate food is less energy-dense than a high-fat food. Excess energy intake is the major risk factor for obesity.
But the case is unique for whole foods that have both complex carbohydrates and unsaturated fats in them, they are nature's superfood. The energy release and the body's metabolism of such foods are different. Such are avocados, nuts and seeds, olives, etc.
So, with other strategies like portioning and healthy food selection, eating carbohydrate-rich foods will contribute less energy than eating high-fat foods of the same weight.
Dietary fibre
Oligosaccharides and other polysaccharides make up what we call fibres in foods. They are usually found only in plant foods. Fibres have been getting a lot of attention in recent times as they have been seen to help prevent various lifestyle diseases in various ways. They are now considered to be a functional food too based on their helpful roles in the body. One of which is how they increase the population and growth of bifidobacteria, a naturally occurring bacteria in the colon which is beneficial for our health.
Fibres are either soluble or insoluble. The insoluble fibres in plant foods are the ones that cannot be digested by the human digestive system, so they are passed to the large intestine and are fed to the gut microbes. they are also called non-glycemic carbohydrates. That is, they do not add to the energy such foods provide through digestion.
Glycaemic index
The glycaemic index (GI) is the metric upon which a carbohydrate food is judged to be able to raise blood sugar levels. The glycaemic index of a food item is the effect such a portion of food has on the blood sugar level. The power that a carbohydrate food has in order to raise blood sugar levels based on how rapidly it is able to metabolise glucose and supply energy is what describes the glycaemic index concept.
Various carbohydrate-containing foods affect blood sugar levels differently. Some foods have a high GI rating while others have less.
A high-GI food has the ability to raise the body's sugar level very fast compared to low-GI foods. Low GI foods are mostly whole in nature, while high GI foods are mostly processed in nature, and have removed fibres and other helpful nutrients in them. Plant foods like fruits which are naturally high GI foods are still considered safe for normal consumption but are under observation in diabetics. Such as mango, pineapples, grapes, raisins, etc.
The GI has been a tool used as an indicator to choose carbohydrate foods that will prevent and reduce lifestyle diseases like obesity, heart failure, hypertension, etc. Foods with a low GI have always been highly recommended by everyone even those with no disease conditions.
Let us look at a couple of foods and their glycaemic index.
Common foods and their recommended serving sizes.
An excerpt from the publication released by the CDC on food serving sizes to help inform meal portions. Below is a list of some known foods and their servings as recommended by the CDC in the management of diabetes.
(Starches)
Bread
Any 1 carbohydrate choice = 15 grams of carbohydrate
Bagel ¼ large bagel (1 oz.)
Biscuit 1 biscuit (2½ inches across)
Bread, reduced-calorie, light 2 slices (1½ oz.)
Cornbread 1¾ inch cube (1½ oz.)
English muffin ½ muffin
Hot dog or hamburger bun ½ bun (¾ oz.)
Naan, chapati, or roti 1 oz.
Pancake 1 pancake (4 inches across, ¼ inch thick)
Pita (6 inches across) ½ pita
Tortilla, corn 1 small tortilla (6 inches across)
Tortilla, flour (white or whole-wheat) 1 small tortilla (6 inches across) or 1⁄3 large tortilla (10 inches across)
Waffle 1 waffle (4-inch square or 4 inches across)
Cereals and Grains (Including Pasta and Rice, cooked)
Barley, couscous, millet, pasta (white or whole-wheat, all shapes and sizes), polenta,
quinoa (all colours), or rice (white, brown, and other colours and types) 1⁄3 cup
Bran cereal (twigs, buds, or flakes), shredded wheat (plain), or sugar-coated cereal ½ cup
Bulgur, kasha, tabbouleh (tabouli), or wild rice ½ cup
Granola cereal ¼ cup
Hot cereal (oats, oatmeal, grits) ½ cup
Unsweetened, ready-to-eat cereal ¾ cup
Starchy Vegetables, cooked
Cassava, dasheen, or plantain 1⁄3 cup
Corn, green peas, mixed vegetables, or parsnips ½ cup
Marinara, pasta, or spaghetti sauce ½ cup
Mixed vegetables (with corn or peas) 1 cup
Potato, baked with skin ¼ large (3 oz.)
Potato, French-fried (oven-baked) 1 cup (2 oz.)
Potato, mashed with milk and fat ½ cup
Squash, winter (acorn, butternut) 1 cup
Yam or sweet potato, plain ½ cup (3½ oz.)
Crackers and Snacks
Crackers, animal 8 crackers
Crackers, graham 3 crackers (2½ inch squares)
Crackers, saltine or round butter-type 6 crackers
Granola or snack bar 1 bar (¾ oz.)
Popcorn 3 cups, popped
Pretzels ¾ oz.
Rice cakes 2 cakes (4 inches across)
Snack chips, baked (potato, pita) About 8 chips (¾ oz.)
Snack chips, regular (tortilla, potato) About 13 chips (1 oz.)
Beans and Lentils
Baked Beans 1⁄3 cup
Beans (black, garbanzo, kidney, lima, navy, pinto, white), lentils (any colour), or peas (black-eyed and split), cooked or canned, drained and rinsed ½ cup
Fruits Any 1 carbohydrate choice = 15 grams of carbohydrate NOTE: the weights listed include skin, core, and seeds.
Applesauce, unsweetened ½ cup
Banana 1 extra-small banana, about 4-inches long (4 oz.)
Blueberries ¾ cup
Dried fruits (blueberries, cherries, cranberries, mixed fruit, raisins) 2 Tbsp.
Fruit, canned ½ cup
Fruit, whole, small (apple) 1 small fruit (4 oz.)
Fruit, whole, medium (nectarine, orange, pear, tangerine) 1 medium fruit (6 oz.)
Fruit juice, unsweetened ½ cup
Grapes 17 small grapes (3 oz.)
Melon, diced 1 cup
Strawberries, whole 1¼ cup
Milk and Milk Substitutes 1 carbohydrate choice = 12 grams of carbohydrate
Milk (non-fat, 1%, 2%, whole) 1 cup
Rice drink, plain, fat-free 1 cup
Yoghurt (including Greek), plain or sweetened with an artificial sweetener. 2⁄3 cup (6 oz.)
*Yogurt is highly variable in carbohydrate content, so check the food label to be sure.
Non-starchy Vegetables 1 serving = 5 grams of carbohydrate
Vegetables, cooked ½ cup
Vegetables, raw 1 cup
Vegetable juice ½ cup
Non-starchy vegetables include asparagus, beets, broccoli, carrots, cauliflower, eggplant, green beans, greens, (collard, dandelion, mustard, purslane, turnip), mushrooms, onions, pea pods, peppers, spinach, squash (summer, crookneck, zucchini), and tomatoes. Some vegetables, such as salad green (lettuce, romaine, spinach, and arugula), have so little carbohydrate that they are considered free foods.