Читать книгу 16 Myths of a Diabetic Diet - Karen Hanson Chalmers - Страница 10

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People with diabetes should avoid potatoes, pasta, rice, and bread because starchy foods raise blood glucose levels and cause weight gain.

FERN: I recently read an article that said Americans should be adding more fiber to their diets and that fiber was also good for blood sugar and weight control. I wanted to start doing this, but I found that most high-fiber foods are also high in carbohydrate. I ended up coming home from the store with my usual purchases. Should I cut out all of the starchy foods and only eat foods with fiber, like raw vegetables and salad?

DIETITIAN: Starches and fiber are recommended for all people—not just those with diabetes. There are a variety of whole-grain starches and other high-fiber foods to choose from, such as whole-wheat pasta instead of white pasta and brown or whole-grain rice instead of white rice. Therefore, whole grains and other carbohydrate foods with fiber, such as fruits and vegetables, should be the most abundant foods on your plate. I will show you how to increase your fiber intake so you will be meeting the current recommendations of 20–35 grams per day.

FERN: But I heard that carbohydrate foods, particularly starches, make you gain weight and are the main cause of diabetes—not sugar!

DIETITIAN: Starches and sugars do not cause diabetes, but weight gain may occur if an excessive amount of any food is eaten. Starch, sugar, and fiber are all types of carbohydrate. Carbohydrate is our main source of fuel, and we need to eat some with each meal. Unfortunately, many Americans eat excessive amounts of carbohydrate because they are not aware of the portion sizes that they are eating. For example, one serving of a whole-grain food could be 1/2 cup cooked oatmeal, 1/3 cup cooked whole-wheat pasta or whole-grain brown rice, one-half of a 100% whole-grain English muffin, or one slice of whole-grain bread. How often do people just eat one slice of bread? The carbohydrate from these foods can add up very quickly at a meal, especially when added to other carbohydrate foods.

FERN: But why are those high-fiber foods so high in carbohydrate?

DIETITIAN: Although fiber is a type of carbohydrate, it is considered “roughage,” so it has little impact on blood glucose levels and provides minimal calories. Therefore, dietary fiber can be deducted from the grams of Total Carbohydrate on a food label. I will be teaching you how to read food labels today. It is important to eat these high-fiber foods every day because roughage helps you feel more full after a meal, helps lower your cholesterol levels, and keeps your digestive tract healthy.

FERN: Okay, I’m ready to learn how to buy healthier foods and begin to add more fiber to my meals. I will also be mindful that it’s the quantity and quality of starches that’s important.

WHAT’S NEXT?

Many people view starchy foods as “bad” foods and try to eliminate many of these foods from their daily intake. When these same people also think of sugar foods as “bad” foods, they end up eliminating many healthy food choices (carbohydrates) as well as good sources of fiber, vitamins, and minerals from their eating plan.

Fern learned from her dietitian that starch and sugar foods are just two of the three types of carbohydrate that belong in everyone’s food plan. Fern also learned that many carbohydrate foods also contain the third type of carbohydrate called fiber, which is the “roughage” that whole grains, fruits, and vegetables provide. Eating the recommended amount of 20–35 grams of fiber per day instead of the average American intake of 10–14 grams per day provides enough fiber to feel satisfied and full after eating a meal without adding extra calories.

Fern’s dietitian also taught her how to keep track of her carbohydrate intake with a meal-planning method called carbohydrate counting (Chapter 7). This meal-planning method gave Fern a carbohydrate allowance to spend at each meal and snack. Much to her surprise, Fern was able to incorporate many new and different foods into her meals. By monitoring how much carbohydrate and fiber she was eating throughout the day, she not only was able to improve her blood glucose levels, but also found it easier to control her weight and food cravings by adding fiber-rich foods. Fern’s last A1C revealed a significant improvement from her previous A1C.

THE OLD AND THE NEW

Before insulin was discovered in 1921, rigid restriction of carbohydrate foods was the only means of controlling blood sugar levels. However, a very small amount of carbohydrate coming from fiber was allowed in certain foods.

Foods were divided into categories based on the amount of carbohydrate and fiber they included. Vegetables such as lettuce, cucumbers, spinach, asparagus, celery, and cabbage were allowed in unlimited quantities. In Joslin’s Diabetic Manual for Doctor and Patient, Dr. Elliot Joslin stated, “These vegetables are a comfort to a diabetic because they contain so little carbohydrate that they can be eaten freely, they are satisfying because of their bulk, and they are rich in vitamins A, B, and C.” The next category included pumpkin, turnip, squash, beets, carrots, onions, and very young, fresh green peas. Then, more mature vegetables such as peas, lima beans, and parsnips were added in limited amounts. The last category was only to be used with caution. Foods such as potatoes, corn, bread, rice, macaroni, and beans were only allowed in very small quantities and had to be carefully measured.

With the discovery of insulin, carbohydrate in the form of starch was gradually increased to a small percentage of the total daily calories, although sugar in most forms, including many fruits, was still forbidden.

Over the next 50 years, as the carbohydrate increased, the percentage of calories from fat gradually decreased because of its known relationship to heart disease. It is important to note that currently, the percentage of carbohydrate is individually based on the dietitian’s nutrition assessment and each individual’s treatment goals.

Home blood glucose monitoring in the 1980s helped reveal how people with diabetes can eat a realistic amount of carbohydrate, based on factors such as blood glucose control, weight, and blood fat levels.

WHAT ARE STARCH AND FIBER?

As we learned in Chapter 2, starch and fiber are commonly known as complex carbohydrates. Starch and fiber are only found in plants, and their structure is composed of 10 or more straight or branched chains of sugar blocks called polysaccharides. Plants store their fuel as starch, so when we eat foods that come from plants, it is converted into glucose for fuel. Because starch is made up of many sugar blocks bonded together, these sugar blocks have to be broken down into their components before they can be used for fuel. The cooking, chewing, and digestive process breaks the bonds holding the sugar blocks together. A couple of hours after eating, all the starch is usually digested and is being used as fuel by the cells of the body.

The best sources of starch are grains, such as rice, wheat, corn, millet, rye, barley, and oats. Legumes (plants from the bean and pea family) and tubers such as potatoes and yams also provide starch.

WHAT IS FIBER?

Fiber is the “roughage” that comes from plant foods that cannot be digested by the human digestive system. It is considered the non-starch polysaccharide and is made up of cellulose, hemicellulose, pectins, gums, mucilages, and lignins. Fiber is what gives plants their structure and is found in all plant foods. Fiber is also the carbohydrate that gives bulk to the digestive tract. Unlike sugar and starch, fiber cannot give us fuel for energy because we cannot break the bonds that hold its sugar blocks together. Therefore, fiber only gives us very limited amounts of fuel and calories.

WHERE ARE STARCH AND FIBER FOUND?

Starch

A strong, healthful meal plan should feature foods rich in starch and fiber, such as breads, cereals, rice, pasta, dry beans, and starchy vegetables. The healthiest choices of breads and cereals are those made from whole grains, in which the whole kernel of grain is left in the flour used to make them. White flour has the bran (coarse outer layer) removed from the kernel of grain for a lighter texture.

Some specific foods in this category, commonly known as the Bread/Starch List, are listed below to give you an idea of how much one serving, or 15 grams of carbohydrate, would be:

Carbohydrate Foods: Breads, Cereals, Rice, Pasta, and Starchy Vegetables

Each of these items contains 15 grams of carbohydrate.

• 1 slice of whole-grain bread

• 1/2 English muffin or small bagel

• 3/4 cup dry cereal or 1/2 cup hot cereal

• 1/3 cup rice, beans, lentils

• 1/2 cup pasta, potato, corn, green peas

• 3 Tbsp flour

• 4–6 crackers

• 3 cups popcorn

Fiber

Fiber is categorized as either soluble or insoluble on the basis of its ability or inability to dissolve in water, respectively. Both soluble and insoluble fibers are called dietary fiber. This term is simply a measure of how much fiber is in a food.

Fiber that dissolves in water is called soluble fiber and includes such foods as citrus fruits, apples, strawberries, oat, wheat, rice bran, barley, leafy vegetables, and dried peas and beans. Soluble fiber cannot retain its structure in the digestion process and forms a gel that binds cholesterol and fats and helps to eliminate them from the body. Soluble fiber also slows the process of food emptying from the stomach. This can mean a slower rise in blood glucose levels after a meal containing adequate fiber.

Fiber that does not dissolve in water is called insoluble fiber and includes such foods as whole-grain cereals, wheat and corn bran, and mature fruits and vegetables, particularly root vegetables. Insoluble fiber works in the colon and has a sponge-like effect that helps push the food through the digestive tract.

WHY DO WE NEED STARCH AND FIBER?

All complex carbohydrates such as grains, breads, cereal, rice, pasta, fruits, vegetables, and legumes are healthy sources of fuel when eaten in moderation. Dessert-type foods that are high in sugar usually do not provide significant fiber, may contain a lot of fat, and are often limited in nutrition. Although sugar (a simple carbohydrate) is also a source of fuel, it should also be eaten in moderation. However, foods like fruits, vegetables, and milk contain forms of sugar as well as many other nutrients and are healthy sources of fuel. Some foods may contain both simple and complex carbohydrate. For example, fruits and vegetables contain both sugar and fiber. Most starches, as well as fruits, vegetables, and legumes, are low in fat and contain many nutrients, including fiber, vitamins, beta carotene, folic acid, zinc, iron, calcium, and selenium. The bulk of our diet, whether we have diabetes or not, should come from complex carbohydrates. They will keep us healthy!

Starch Is Used as a Fat Replacer

When fats are taken out of foods, the most common ingredient used to substitute the fat is a carbohydrate-based replacer in the form of a modified food starch. These food starches provide thickening and gelling abilities. They also stabilize, add texture, and provide structure to an otherwise unstable product. Common foods that may contain fat replacers are frozen desserts, baked goods, sauces, salad dressings, cheese, and gelatin. Often there is more than one fat replacer in the same food. You may recognize some of these carbohydrate-based fat replacers that come from corn, potato, rice, and tapioca, as well as ingredients such as polydextrose and maltodextrin. These fat replacers may cut down the amount of fat in a product but will raise the total carbohydrate content of these foods. It is very important to look at the grams of total carbohydrate on a food label when purchasing any low-fat or fat-free product because these products commonly contain more carbohydrate than expected. Remember that carbohydrate has the biggest impact on blood glucose.

Here’s an example. Let’s say you’re looking at two bottles of blue cheese salad dressing—one is a light dressing and the other is a fat-free dressing.

As you can see above, there’s quite a bit of difference between the two dressings. This demonstrates the need to read food labels and monitor blood glucose after eating these foods to better understand how they will affect you.

THE UPSIDE AND THE DOWNSIDE OF STARCH AND FIBER

The good news for people with diabetes is that all carbohydrate foods can fit into a healthy diet, including starch or fiber. The body breaks down all carbohydrate, except fiber, into glucose (blood sugar) at the same rate, although this may be influenced by factors such as the presence of fat and protein in the same meal. Therefore, first and foremost, it is important to control the total amount of carbohydrate you eat.

The Downside

1. Eating a lot of carbohydrate from starch can lead to weight gain, even with the added benefits of vitamins, minerals, and fiber. Excess calories from any food will be stored as body fat.

2. Starchy foods, such as cake, cookies, muffins, sweet breads, and cereals, have higher amounts of total carbohydrate because of the starch plus the added sugar. Even though these foods may be part of a healthy diet, they may lead to higher blood glucose levels and weight gain. Therefore, the portion sizes should be carefully monitored.

3. If taken in excessive amounts, even fiber may be harmful. If a lot of fiber is consumed in a short period of time, it can cause intestinal gas, bloating, cramps, and constipation. Eating too much fiber, which absorbs water, can also lead to dehydration. When increasing fiber in your diet, do it gradually, giving your body time to adjust, and increase the amount of fluids you drink to at least 6—8 cups per day. Fiber in very large amounts can also interfere with the absorption of some minerals, such as zinc, iron, magnesium, and calcium.

The Upside

1. Whole-grain, high-fiber foods tend to be low in fat and calories (fiber does not provide calories or fuel) and can often prevent you from eating too much fat and protein from animal products. This can reduce your risks of heart disease, overweight, constipation, and high blood glucose levels.

2. Whole-grain, high-fiber foods make us feel full and satisfied at meals and snacks without adding extra calories, and they help prevent overeating or going back for an extra helping. These foods also take longer to chew, so your brain has adequate time to notify your stomach that you are full.

3. Whole-grain, high-fiber foods form a large bulk in the intestine and help push the food through the digestive tract at a faster rate. This results in less pressure on the walls of the intestine, which reduces the risk of constipation, hemorrhoids, and diverticulosis.

4. Research has shown that by eating more soluble fiber, you can reduce risk of heart disease by lowering your LDL (bad) cholesterol.

HERE’S WHAT YOU CAN DO

1. Get healthy. A healthy fiber intake should be between 20 and 35 grams each day. This means that many Americans would have to double their intake.

2. Variety can add fiber. Eat a variety of carbohydrate foods to ensure that you get the health benefits from both soluble and insoluble fiber.

3. Eat more vegetables. Eat three or more servings of vegetables a day: 1 serving equals 1/2 cup cooked or 1 cup raw vegetables.

4. Eat two or more servings of fruit each day. One serving equals 1 small piece of fruit, 1/2 cup canned fruit, or 1 cup of cut-up fresh fruit.

5. Eat at least six servings of grain products and legumes a day. One serving equals 1 slice whole-grain bread, 1/3 cup brown rice or pasta, 1 small potato with the skin, or 1/2 cup legumes or oatmeal. Tip: Add a handful of beans to a salad.

6. Eat fewer processed foods. Make sure the label’s first ingredient on breads, cereals, and crackers is whole-grain flour, such as whole-wheat flour instead of just wheat flour or enriched wheat flour. Whole-wheat bread is not the same as wheat bread.

7. Substitute items. Use low-fat, low-calorie toppings (for example, 1 Tbsp salsa or 1 Tbsp nonfat sour cream) on starchy foods instead of the high-fat toppings, which add too many calories.

8. Get more from your foods. For extra fiber, leave the skin and peels on fruits and vegetables, if possible. Fruits with seeds, such as raspberries and strawberries, also contain a lot of fiber.

9. Use whole-grain flours when cooking and baking.

10. Get help before taking supplements. Check with your doctor or dietitian before taking a fiber pill or supplement. Fiber replacements lack other nutrients found in actual fiber-containing foods and often don’t contain that much fiber anyway.

11. Add a few sprinkles. Sprinkle some ground flaxseed into your morning cereal or add it to your salad or yogurt.

SUMMARY

For years, starch has been thought of as the “fattening” ingredient in foods. Don’t forget, however, that many starchy foods are eaten with added fat! When we eat potatoes, bread, corn, pasta, and vegetables, we rarely eat them without putting some sort of fat on them—butter, margarine, sour cream, cream cheese, and cheese sauce. What about a pasta meal? Not only are we served large quantities of pasta, but we also add several slices of Italian bread, breaded cutlets, and tomato sauce, with croutons on the salad, most of which contain carbohydrate in the form of starch. By the end of the meal, the carbohydrate has added up to an excessive amount. It isn’t the starch or the pasta that causes weight gain and high blood glucose levels, it’s the total amount of calories from carbohydrate and the fat and protein that was consumed.

Three nutrients provide fuel to the human body: carbohydrate, protein, and fat. Protein foods provide the most expensive fuel, take longer to empty from the stomach, and do not provide the quantity of fuel that carbohydrate does. Because Americans already eat too much protein and animal products, which puts us at a high risk for heart disease, many can not afford to add more, either financially or in terms of our health. Unfortunately, the brain and the central nervous system do not use the fuel from fatty foods efficiently. Fat also provides twice as many calories as carbohydrate and protein and is linked to insulin resistance, overweight, and obesity when consumed in large amounts. So that leaves us with carbohydrate, the major fuel source for our body. Food starch is probably the most important fuel source for energy and the most preferred fuel used by our brains and nervous system.

Contrary to what you hear from promoters of the many low-carbohydrate diets now on the market, low-carbohydrate diets dismiss evidence offered by well-known researchers and proven studies and condemn carbohydrate as the culprit in the development of diabetes, high blood sugars, and weight gain. The 2005 U.S. Department of Agriculture Dietary Guidelines actually directs Americans on how to eat in a balanced and healthy way by eating plenty of carbohydrate and fiber-rich foods, moderate amounts of protein, and low amounts of fat.

YOUR TURN

Now it’s your turn to recall some key points from this chapter. Let’s see how you do!

1. All Americans should be eating 20—35 grams of fiber per day, whether they have diabetes or not. True or false?

2. Fiber is only found in plant foods. True or false?

3. The fiber most helpful in lowering cholesterol and fats in the blood is ____________ fiber.

4. The one type of carbohydrate that helps us feel “full” and satisfied after a meal is ______________.

See APPENDIX A for the answers.

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