Carbohydrates

What is a carbohydrate?

11-25-2013 1-03-36 PMA carbohydrate is a component of food that supplies energy, called calories, to the body. It is one of the three macronutrients, along with proteins and fats. There are three broad categories of carbohydrates, sugars (simple carbohydrates), starches (complex carbohydrates and are composed of long chains of glucose), and fiber. Except for fiber and resistant starch, carbohydrates cause more and faster blood glucose rises than the other macronutrients. We can reap the health benefits of good carbs by choosing carbohydrates that are full of fiber. These are carbs that get absorbed slowly into our systems and help us to avoid spikes in blood sugar levels.

To meet the body’s daily nutritional needs while minimizing risk for chronic disease, adults should get 45% to 65% of their calories from carbohydrates, 20% to 35% from fat, and 10% to 35% from protein. The only way to get fiber is to eat plant foods, such as fruits and vegetables. To determine if a carb is a “good” carb, you must consider its fiber content (unless it’s a naturally low-fiber food like skim or low-fat milk). Fiber is the part in plant foods that humans can’t digest so it slows down the absorption of other nutrients eaten at the same meal, including carbohydrates.  This slowing down may help prevent peaks and valleys in your blood sugar levels, reducing your risk for type 2 diabetes.  Certain types of fiber found in oats, beans, and some fruits can also help lower blood cholesterol and as an added plus, fiber helps people feel full, adding to satiety.

Examples of “good carbs”: whole grains, vegetables, fruits, and beans.

Examples of “bad carbs”: white bread and white rice.

11-25-2013 1-04-00 PM

Types of Carbohydrates: 

Your body uses carbohydrates to make glucose which is the fuel that gives you energy and helps keep everything going.  It can use glucose immediately or store it in your liver and muscles for later when it is actually needed. There are two main types of carbohydrates, complex and simple.  Starch and dietary fiber are the two types of complex carbohydrates. Starch must be broken down through digestion before your body can use it as a glucose source. Dietary fiber, also known as roughage or bulk, includes all parts of plant foods that your body can’t digest or absorb. Instead, it passes relatively intact through your stomach, small intestine, and colon and then out of your body. Dietary fiber can be found in vegetables, fruits, and whole grain foods.  Starch is found in certain vegetables, such as potatoes, dry beans, peas, and corn, breads, cereals, and grains. Dietary fiber can also be listed on labels as soluble fiber or insoluble fiber. Soluble fiber is found in foods such as oatmeal, oat bran, nuts and seeds, most fruits, dry beans and peas.  Insoluble fiber found in foods such as whole wheat bread, barley, brown rice, couscous, bulgur or whole grain cereals, wheat bran, seeds, most vegetables, and fruits.  Each has important health benefits so eat a variety of these foods to get enough of both. You’re also more likely to get other nutrients that you might miss if you just chose 1 or 2 high-fiber foods.

So how much dietary fiber do you need daily? 

It’s recommended that you get 14 grams of dietary fiber for every 1,000 calories that you consume each day. At first, you may find it challenging to eat all of your daily fiber grams. Just take it slowly and try to choose higher-fiber foods more often. Easy tips to increase fiber would be to choose whole fruits more often than fruit juice, eat two vegetables with your evening meal, keep a bowl or bag of veggies already washed and prepared your refrigerator, and make a meal around legumes (dried peas or beans) instead of meat, or start your day with a whole grain breakfast cereal low in added sugar topped off with fruit for even more fiber. In winter months it may be more of a challenge to find fresh fruit, so use frozen fruit.

Whole grains vs. “Refined” grains:

Whole grains are a good source of fiber and nutrients. Whole grains refer to grains that have all of the parts of the grain seed (sometimes referred to as the kernel). These parts of the kernel are called the bran, the germ, and the endosperm. If the whole grain has been cracked, crushed, or flaked (as in cracked whole grain bread or flake cereal), then the whole grain must still have about the same proportions of bran, germ, and endosperm to be called a whole grain. When whole grains are processed, some of the dietary fiber and other important nutrients are removed. A processed grain is called a “refined” grain.

Some refined grain products have key nutrients, such as folic acid and iron, which were removed during the initial processing and added back. These are called enriched grains. White rice and white bread are enriched grain products. Some enriched grain foods have extra nutrients added. These are called fortified grains.

Some excellent whole grain choices are:

  • brown rice and wild rice
  • buckwheat or bulgur (cracked wheat)
  • millet, quinoa, triticale
  • whole-grain barley, corn, oats/oatmeal, whole rye, whole wheat 

Simple carbohydrates include sugars found naturally in foods such as fruits, vegetables milk, and milk products. Simple carbohydrates also include sugars added during food processing and refining. In general, foods with added sugars have fewer nutrients than foods with naturally-occurring sugars.

In an effort to avoid these added sugars, look for these ingredients when reading labels and note that the closer to the top of the list, the more of that sugar is in the food:

  • Brown sugar, corn sweetener, or corn syrup
  • Dextrose, Glucose, Fructose
  • Fruit juice concentrates
  • High-fructose corn syrup
  • Lactose or  Maltose
  • Malt syrup, molasses, honey
  • Raw sugar, sucrose, sugar, syrup

Sugars and refined grains and starches supply quick energy to the body in the form of glucose which is a good thing if your body needs quick energy, for example if you’re running a race or competing in sports. The better carbs for most people are unprocessed or minimally processed whole foods that contain natural sugars, like fructose in fruit or lactose in milk. Added sugars supply calories but few or no nutrients. The USDA recommends that we get no more than 6% to 10% of our total calories from added sugar, which equates to approximately 9 teaspoons a day for most Americans.

GI Scale/Glycemic Load: 

All carbohydrates are not all created equal. Even with equal amounts of carbohydrate, some foods will cause a higher blood sugar rise than others. The higher the glycemic index (GI), the higher the glucose response in the blood. Many low carb diets take glycemic index and/or glycemic load into account when making diet recommendations, aiming to avoid a large blood sugar rise. There are several factors that affect GI such as processing, ripeness of fruit, protein content, fat content, fiber, and how small the particles are processed. For example whole grains have a relatively low GI, but grinding them into flour significantly increases the GI.

glycemic-load-glycemic-index

One criticism of the glycemic index is that since it the scale was created on a standard amount of carbohydrate per food (50 grams), it doesn’t give people information about the amount of food they are actually eating by not taking serving size into account. One example of this would be carrots. Carrots do have a high glycemic index, but to get 50 grams of carbohydrate from carrots, you have to eat 4 cups of chopped carrots. For this reason, the concept of the glycemic load was created, which does take serving size into account. The glycemic load uses a formula to take the number of grams of carbohydrate in the serving, multiply by the glycemic index, and divide by 100. Theoretically, if a food has glycemic load of one point, it would raise the blood sugar as much as one gram of glucose.

Some nutritionists use the following categories for a diet’s glycemic load:

  • Low Glycemic Load: Less than 80 points per day
  • Medium Glycemic Load: 80-120 points per day
  • High Glycemic Load: Over 120 points per day

Examples of the glycemic load of some common foods:

  • 2 oz. peanuts: 1
  • 1/2 large grapefruit: 3
  • 1/2 cup pinto beans: 6
  • 1 cup corn flakes: 21
  • 1 cup brown rice: 23
  • 1 bagel, 3.5 inches across: 25
  • 1 baked potato, 3 inches in diameter (170 grams): 28
  • 1 cup white rice: 33

A basic list that I found on-line of the Glycemic Index & Glycemic Load that is helpful:

http://www.health.harvard.edu/newsweek/Glycemic_index_and_glycemic_load_for_100_foods.htm

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