Diabetes is a disease in which the glucose in the blood is higher than normal. High blood glucose is called hyperglycemia. Glucose is a type of sugar that comes from foods containing carbohydrates and is found in everyone’s blood. Glucose is transported through the blood to all tissues and organs to be used for energy. Blood glucose should not be too low (hypoglycemia) or too high (hyperglycemia). The body usually keeps blood glucose within a certain range by using stored glucose when needed, or storing the glucose when it is not needed. The body is normally able to control blood glucose levels using a hormone called insulin. Insulin is released by the pancreas in response to increased levels of glucose in the blood. With diabetes, however, the body has trouble making or using insulin. For this reason, blood glucose levels rise and hyperglycemia occurs.
How does food turn into glucose?
To understand and manage diabetes well, you must know what happens to food when you eat. Food is made of
Carbohydrates, proteins, and fats all contain calories, and can all be used for energy. Too many calories can cause weight gain. Weight gain usually also results in higher blood glucose levels because the body becomes less sensitive to insulin. Vitamins, minerals, and water do not contain calories, cannot be used for energy, and do not affect blood glucose.
Carbohydrates, proteins, and fats all contain calories
When we eat, carbohydrates, proteins, and fats are digested and broken into smaller parts. Once broken down, these parts will affect blood glucose differently depending on how they are absorbed and how the body uses them. Almost all the carbohydrate eaten will be converted into glucose in the body. The only carbohydrates not changed to glucose are those that cannot be digested, like fiber.
So the amount of food that’s eaten can affect blood glucose – too much can lead to weight gain, insulin resistance, and higher blood glucose levels. Carbohydrates affect blood glucose, because carbohydrates are digested and broken into smaller parts that are primarily glucose units.
Is glucose bad for people with diabetes?
No, glucose is not bad for people with diabetes. Everyone, including people with diabetes, needs glucose for energy. We need energy to play, exercise, and work, but we also need it for everyday body functions, like breathing, digesting, and making blood cells. Most of the glucose in our body comes from eating carbohydrates. People without diabetes are able to keep their blood glucose levels in a normal range regardless of the amount they eat. For people with diabetes, it is harder to keep blood glucose in a normal range. For this reason, people with diabetes need to balance the amount of food that they eat (especially food that contains carbohydrates) with their medication and activity level.
Why do some people have high blood glucose levels?
Glucose primarily comes from the food we eat. Mainly foods containing carbohydrates are broken down into glucose and used for energy. Once food is broken down into glucose, it enters the blood and is carried to all the cells of the body. However, in order for glucose to enter the cell, a special helper and cell receptor are needed. The helper that glucose needs to enter the cell is called insulin. Insulin is a hormone made by the pancreas. Cell receptors are like doorways into a cell. A cell can have many receptors.
To imagine how glucose, insulin, and cell receptors work, think of your car. To park in your garage, you need a garage door and a garage door opener. Glucose is like your car, the cell receptor is like the garage door, and the insulin is like the opener.
If your body does not make enough insulin or if the insulin or the cell receptors do not work the way they should, glucose cannot get into your cells. Instead, glucose stays in your blood causing hyperglycemia. A complete lack of insulin results in type 1 diabetes. Insulin or cell receptors that do not work properly result in type 2 diabetes.
Are there different types of diabetes?
There are three main types of diabetes: type 1 diabetes, type 2 diabetes, and gestational diabetes.
Type 1 Diabetes
Type 1 diabetes can occur at any age, but is most often diagnosed early in life. Type 1 diabetes is called an autoimmune disease, because the immune system attacks the person’s own cells. In this type of diabetes, cells in the pancreas that produce insulin are the target of the body's immune system and are eventually destroyed. For this reason, people with type 1 diabetes produce no insulin so glucose cannot get into the cells.
Symptoms of type 1 diabetes include:
Thirst (polydipsia)
Extreme hunger (polyphagia)
Excessive urination (polyuria)
Weakness or tiredness
Type 2 Diabetes
Type 2 diabetes is the most common form of diabetes. Ninety-five percent of the people who have diabetes have type 2. Although it was once thought that type 2 diabetes occurred only in adults, it is now known that people can develop type 2 diabetes at any age. With type 2 diabetes, the receptors on the cells become resistant to insulin and therefore cannot let glucose into the cell. Type 2 diabetes may also result if the body does not make enough insulin. Both problems with the cell receptor or with the amount of insulin produced, lead to high blood glucose levels. Being overweight and inactive increases the chance of developing type 2 diabetes.
Insulin resistance is a condition when normal insulin levels do not result in glucose entry into the cell. Higher than normal insulin levels in the blood occur in insulin resistance.
People who have insulin resistance are usually overweight or obese. They may have a normal blood glucose, be diagnosed as “pre-diabetes”, or have type 2 diabetes. People who have a normal blood glucose may have no symptoms of insulin resistance but usually develop pre-diabetes. Those with pre-diabetes usually develop type 2 diabetes. The exception to this progression occurs when overweight or obese people lose weight, eat a healthy diet, and exercise regularly.
Not everyone who is obese or overweight will develop insulin resistance, although a lot of people will. Genetics, diet, and activity levels all can play an important role in how well insulin and glucose interact.
Symptoms of type 2 diabetes include:
Frequent urination (polyuria)
Thirst (polydipsia)
Blurred vision
Unintentional weight gain or weight loss, although little weight change may occur
Fatigue
Many people have no noticeable symptoms
Gestational Diabetes
Gestational diabetes is a form of diabetes that occurs during pregnancy. When a woman becomes pregnant there are many hormonal changes that take place. These changes, especially in the later stages of pregnancy, can affect the mother’s sensitivity to insulin. When the mother becomes resistant to insulin, her cells do not let glucose in and her blood glucose levels rise. When blood glucose levels rise above a certain level, gestational diabetes is diagnosed. Doctors often check women’s blood glucose levels during their pregnancy because high blood glucose levels can cause complications during the pregnancy or after the baby is born. These complications include infants of high birth weight, increased risk of cesarean delivery, infant respiratory distress syndrome, infant hypoglycemia following delivery, and infant jaundice. The presence of fasting hyperglycemia greater than 105mg/dl may be associated with increased risk of fetal malformations and death. Although gestational diabetes usually goes away after the baby’s birth, women with this type of diabetes are at high risk for developing type 2 diabetes later in life.
How is diabetes diagnosed?
There are two types of tests that can be used to diagnose diabetes or pre-diabetes: a Fasting Plasma Glucose Test (FPG) or an Oral Glucose Tolerance Test (OGTT). This test should be performed by a doctor for a diagnosis to be made and often needs to be repeated on at least two occasions.
According to the American Diabetes Association, a FPG test that results in a fasting blood glucose level between 100 and 125 mg/dl signals pre-diabetes. A person with a fasting blood glucose level of 126 mg/dl or higher has diabetes.
In the OGTT, a person's blood glucose level is measured after a fast and two hours after drinking a glucose-rich beverage. If the two-hour blood glucose level is between 140 and 199 mg/dl, the person tested has pre-diabetes. If the two-hour blood glucose level is 200 mg/dl or higher, the person tested has diabetes.
Food Groups and Diabetes
What are macronutrients?
Macronutrients are nutrients that provide calories (energy). Nutrients are substances needed for growth, metabolism, and other functioning. Since “macro” means large, macronutrients are nutrients needed in large amounts. There are three categories of macronutrients:
Carbohydrates
Proteins
Fats
While each of these macronutrients provides calories, the amount of calories that each one provides varies. One gram of carbohydrate or protein provides 4 calories per gram. One gram of fat provides 9 calories per gram. If you looked at the Nutrition Facts label of a food product and it said 12 grams of carbohydrate, 0 grams of fat, and 0 grams of protein per serving, you would know that this food has about 48 calories per serving (12 grams carbohydrate multiplied by 4 calories for each gram of carbohydrate = 48 calories). The only other substance that provides calories is alcohol, which provides 7 calories per gram. Alcohol, however, is not a macronutrient, because we do not need it for survival.
Macronutrients are not the only things that we need for health. Our body also needs water and micronutrients. According to the 2004 Dietary Reference Intakes (DRIs), adult men need about 3.7 liters of water per day, and adult women need about 2.7 liters of water per day. Micronutrients are nutrients that our bodies need in smaller amounts, and include vitamins and minerals.
Why are foods put together in groups?
For people with diabetes, it is important to understand what foods are made of so that blood glucose levels can be more easily controlled. Memorizing the exact amount of carbohydrate in all the foods that we eat would be almost impossible and impractical. Fortunately there are six main food groups:
The Starch and Starchy Vegetables Group
The Fruit Group
The Vegetable Group
The Meat, Meat Substitutes, Eggs, and Cheese Group
The Milk and Yogurt Group
The Fats and Oils Group
It is important to eat foods from each group every day. The type and the amount of food that you chose to eat can have either positive or negative effects on your health.
What counts as a portion or serving?
The amount of food that you eat from the food groups can impact both your weight and blood glucose level. For instance, eating too much food from any food group is likely to cause weight gain. This weight gain can lead to higher blood glucose levels. Eating too much from the starch and starchy vegetables group, the fruit group, or the milk and yogurt group will cause your blood glucose levels to rise if you have diabetes. But how much food is too much, and what is a portion or serving size?
We sometimes think of what we put on our plate as a portion and a serving. While what we put on our plate may be considered a portion, it usually isn’t a serving in the way that dietitians think of servings. To care for yourself and your diet, you will need to begin thinking like a dietitian, and recognize that portions and servings are different.
Since portion sizes can vary from person to person, they are not a good measure of how much you should eat in one day. Serving sizes, however, are much more strictly defined and do not vary from person to person. The American Dietetic Association and the American Diabetes Association have set serving sizes for foods in the various food groups. These serving sizes make it easier to identify how many calories, and how much carbohydrate, fat, and protein are in various foods.
It is important to remember that serving sizes may not be the same as the serving sizes listed on Nutrition Facts labels. Companies that make food products, for the most part, are allowed to decide what the serving size on their product should be. This serving size is often based on how much an average person would eat. For instance, a Nutrition Facts label on a package of bread might list one serving as two slices of bread with 110 calories and 21 grams of carbohydrate. However, one serving from the starch group is defined by the American Dietetic Association and the American Diabetes Association as one slice of bread with about 80 calories and 15 grams of carbohydrate. Serving sizes on Nutrition Facts labels vary depending on the product and the company that makes it. For this reason, it is always important to look at the calories and macronutrients as well as the serving sizes listed on the Nutrition Facts labels.
The Starch and Starchy Vegetables Group
Foods in this group include cereals, grains, pasta, breads, and crackers. All of these foods are grouped together, because the majority of the calories they contain come from carbohydrates, these foods also contain some protein and sometimes fat. Cooked beans, peas, and lentils also belong in this group, but because they contain more protein they are also part of the meat and meat substitutes group. For this reason, eating one serving of beans, peas or lentils will count as one serving from the starch group and one serving from the meat group. This concept is explained in further detail in the section titled The Meat and Meat Substitutes Group.
People with diabetes do not need to avoid foods found in the starch and starchy vegetables group. In fact, people with diabetes need to eat foods from this group to help meet their daily requirement for calories, macronutrients, fiber, vitamins, and minerals and for overall good health. Foods in this group, however, do contain carbohydrates that can raise blood glucose. It is important to space servings from this group (and the milk and fruit groups) evenly throughout the day, and only eat the number of serving that your doctor or dietitian has recommended. This will help to keep blood glucose levels within your target range.
One Serving from the Starch and Starchy Vegetable Group
One serving from the starch and starchy vegetables group contains about 80 calories, 15 grams of carbohydrate, 3 grams of protein, and 0-1 grams of fat.
Examples of one serving from this group would include:
- One slice of bread
Half of a bun or small bagel
1/4 of a baked potato
1/3 cup pasta (cooked)
1/3 cup rice (cooked)
- Corn
Dried beans
Lima beans
Peas
Potatoes
Sweet potatoes
Winter squash
Tips for Choosing Foods from the Starch and Starchy Vegetable Group
Choose starches made with little fat as often as you can. For example, choose a slice of toast instead of a doughnut.
Choose foods made from whole grains to get more fiber. Whole grain foods include whole wheat bread, whole grain pastas, and whole bran cereal. (Three grams of fiber per serving would be a good fiber choice.)
Starchy vegetables made with fat count as one serving from the starch group and one serving from the fat group. These foods would include French fries and yams with butter.
Always check the Nutrition Facts labels of foods the first time you buy them so you will know how many servings from the Starch Group the products contain.
The Fruit Group
Foods in this group include fresh, frozen, canned and dried fruit as well as fruit juices. All fruits are grouped together because all of their calories come from carbohydrates. Fruits contain very little protein and no fat.Although foods with carbohydrates raise blood glucose, people with diabetes do not need to avoid fruits or fruit juice. In fact, it is important that everyone eat at least 2 servings of fruit every day. However, as with other foods, fruits need to be part of the meal plan.
One Serving from the Fruit Group
One serving from the Fruit Group contains about 60 calories and 15 grams of carbohydrate.
Examples of one serving from this group would include:
- One small piece of fresh fruit (like an apple or orange that is the size of a tennis ball)
1/2 cup of canned or fresh fruit (like fresh pears or peaches canned in water)
1/2 cup of unsweetened fruit juice (like unsweetened orange juice)
1/3 cup of some fruit juice that is naturally higher in carbohydrates (like prune juice or cranberry juice)
1/4 cup dried fruit (like raisins)
Tips for Choosing Foods from the Fruit Group
Choose fresh fruits more often than canned fruits or fruit juices. Unlike whole fruits, canned fruits and fruit juices are often higher in sugar and calories, and fruit juices usually do not have any fiber.
When choosing canned fruit, choose fruit canned in its own juice, not a syrup-packed variety. If choosing a generic product that is not labeled as “packed in its own juice” look at the Nutrition Facts label. Talk to your dietitian or health care provider if you have any questions about choosing appropriate canned fruit.
Dried fruit, when compared to the same amount of fresh or frozen fruit, will always be the higher in calories.
Read the Nutrition Facts label if you are unsure of how many fruit servings a certain amount of food contains. For fresh fruit that does not have a Nutrition Facts label, follow the above guidelines under the section titled “one serving from the fruit group.”
The Vegetable Group
Foods in this group include vegetables that contain few calories, carbohydrates, and protein. These non-starchy vegetables may be fresh, frozen, or canned vegetables. Vegetable juices are also found in this group.
Non-starchy vegetables are a real nutrition bargain. They are rich in vitamins and minerals. Vegetables are also low in calories and fat, and they are a good source of fiber. Since vegetables are lower in carbohydrates than fruit, they can often be eaten in much larger servings and more often than fruit.
One Serving from the Vegetable GroupOne serving from the vegetable group contains about 25 calories, 2 grams of carbohydrate, and 5 grams of protein.
Examples of one serving from this group would include:
1/2 cup cooked vegetables (cooked spinach or cooked broccoli)
1 cup raw vegetables (lettuce or mushrooms)
1/2 cup of vegetable juice
Tips for Choosing Foods from the Vegetable Group
Choose fresh or frozen vegetables more often than canned vegetables or vegetable juices.
Choose plain tomato sauce since this is in the vegetable group instead of ready-made tomato-based pasta sauces (like Ragu®, Prego® or Classico® pasta sauces) that have more carbohydrates. However, always check the Nutrition Facts label, because some pasta sauces may have the same number of calories and carbohydrates as tomato sauce.
Read the Nutrition Facts label if you are unsure of how many vegetable servings a food contains. For fresh vegetables that do not have a Nutrition Facts label follow the above guidelines under the section titled “one serving from the vegetable group.”
The Meats, Fish, Meat Substitutes, Eggs and Cheese Group
Foods in this group include meats (like beef, chicken, and pork), fish (like salmon, tuna, and shrimp), meat substitutes (like tofu, and products that resemble meat or fish but are made with soy), eggs, and cheese. These foods are grouped together, because the majority of the calories they contain come from protein and/or fat. Cooked beans, peas, and lentils also are in this group because of the protein that they contain, but are also considered starchy vegetables because of their carbohydrate content. While some meat substitutes and cheeses may contain small amounts of carbohydrate, the main macronutrients in these foods are protein and fat. Nuts are also often placed in this group because nuts contain some protein, but they are also high in fat.
Protein is very important in our daily diet. We need protein to maintain muscles, make enzymes, and keep our immune system working well. However, items in this group can be high in calories. Also, meat, eggs, and cheeses in particular can be high in saturated fat and cholesterol. People with diabetes need to make heart-healthy choices when choosing foods from this group because of their increased risk for cardiovascular complications. See the section titled Eating for Cardiovascular Health.
One Serving from the Meats, Fish, Meat Substitutes, Eggs and Cheese Group
One serving from the meats, fish, meat substitutes, eggs, and cheese group usually contains about 7 grams of protein, but the amount of calories, carbohydrate, and fat in foods from this group varies depending on the type of food. For instance some meats like salami contain a higher amount of fat than lean meats like chicken. Foods in this group with higher amounts of fat per serving also contain more calories per serving. The carbohydrate content of foods in this group also varies. For instance, meats and eggs do not contain any carbohydrate, but beans and soy do. Chicken and fish will contain less fat than hot dogs or cheese.
Examples of one serving from this group would include:
1 ounce cooked lean meat, poultry, or fish
1 ounce cheese
1/2 cup tofu
1 egg
1 tablespoon of peanut butter
1 ounce of soyburger
The serving sizes of foods in this group are very small. Since not many people eat one ounce of meat or cheese at a time, 3 servings (3 ounces) of food from this group is usually considered to be a portion. Ask your health care provider or dietitian how many servings you should eat from this group every day.
Nuts, Beans, and Soy Products
Nuts, beans, and some soy products are good sources of fiber since they are also vegetables, or legumes. Although nuts contain both fiber and protein, they are also high in fat. When nuts are eaten in smaller amounts, they are usually considered to be a serving from the fat group, but when they are eaten in larger amounts they are considered a serving of high-fat meat. For instance ½ tablespoon of peanut butter is considered to be one serving from the fat group, but one tablespoon of peanut butter is considered one serving from the meat and meat substitutes group. Like nuts, soybeans and beans contain both carbohydrate and protein. Unlike nuts, however, they are usually low in fat. One cup of whole soybeans or beans contains about 8 grams of fiber. Processing will lower the fiber content of some soy products, such as tofu.
Tips for Choosing Foods from Meats, Fish, Meat Substitutes, Eggs and Cheese Group
Choose foods from this group that have between 35 and 60 calories and 0-3 grams of fat per serving whenever possible to reduce your saturated fat and total fat intake. Fish and skinless white meat poultry are good choices, as are lean whole meats like lean pork chops or lean steaks.
Read Nutrition Facts labels carefully. If any product contains close to 15 grams of carbohydrate as well as 7 grams of protein per serving, it would count as both a meat and starch serving.
Choose foods from this group that are low in cholesterol such as poultry, meat substitutes made from soy, or some beef items.
The Milk and Yogurt Group
Foods in this group include milk and yogurt. These foods are grouped together, because they contain similar amounts of carbohydrate and fat. While milk and yogurt usually contain similar amounts of protein and carbohydrates, they can vary in their fat content.
One Serving from the Milk and Yogurt Group
One serving from the Milk and Yogurt Group usually contains about 12 grams of carbohydrate and 8 grams of protein, but the amount of fat and calories in these foods varies. For instance, one cup of fat-free milk contains about 90 calories and 0 grams of fat, but one cup of whole milk contains about 150 calories and 8 grams of fat. Check the Nutrition Facts labels of these products to identify the amount of calories and fat that they contain.
Examples of one serving from this group would include:
1 cup milk ( fat-free, ½%, 1%, 2% or whole)
1 cup soy milk (low fat, or fat-free)
2/3 fat-free yogurt (flavored or plain)
3/4 cup low-fat yogurt
Tips for Choosing Foods from the Milk and Yogurt Group
Choose fat-free, low-fat, or reduced-fat products from this group whenever possible. These products contain less fat and fewer calories.
Read the Nutrition Facts labels of yogurts carefully. Yogurt cups often vary in size so it is important to check the serving size of yogurts. Also, the calorie content of yogurt varies quite a bit, because some companies add sugar, syrup, artificial sweeteners, and/or fruit.
Read the Nutrition Facts label if you are unsure of how many milk or yogurt servings a certain amount of food contains.
The Fats and Oils Group
Foods in this group include butter, margarine, salad dressing, mayonnaise, sour cream, oils, lard, and nuts. The foods in this group are grouped together because they contain similar amounts of calories and fat per serving and, with the exception of nuts, contain little protein or carbohydrates. Although fat is often thought of as being unhealthy for you, fat is essential for life. We need a certain amount of fat each day. The hard part is deciding what types and how much fat to eat.
There are four main types of fat, polyunsaturated, monounsaturated, trans, and saturated fats. All of these names describe the chemical structure of the different fats. Most foods contain a mixture of these four types of fats, but they are grouped by the type of fat that is present in the largest amount. While it is true that all fat is high in calories and that too much of any type of fat may be unhealthy, some types of fat are better for you than others. Saturated and trans fats have been shown to increase the risk for heart disease, but polyunsaturated and monounsaturated fats have been shown to have no effect on or decrease the risk for heart disease. See the section titled Eating for Cardiovascular Health.
One Serving from the Oils and Fats Group
One serving from the Oils and Fats Group contains about 45 calories and 5 grams of fat. Examples of one serving of monounsaturated and/or polyunsaturated fats include:
- 1 teaspoon margarine
1 teaspoon mayonnaise
1 tablespoon reduced-fat mayonnaise
1 teaspoon oil (corn, canola, vegetable)
1 tablespoon salad dressing
2 tablespoons reduced-fat salad dressing
6 almonds
10 peanuts
Examples of one serving of saturated fats include:
- 1 teaspoon butter
1 teaspoon shortening or lard
2 tablespoons sour cream
3 tablespoons reduced-fat sour cream
1 tablespoon cream cheese
Tips for Choosing Foods from the Fats and Oils Group
Choose foods that contain more polyunsaturated or monounsaturated fats rather than foods that contain saturated or trans fats.
Choose low-fat or reduced-fat options when calories are similar to or less than the full fat product. Sometimes the fat in low-fat products is replaced with carbohydrate, making a low-fat product that is still high in calories. For this reason, it is always important to check the calorie and macronutrient content of low-fat foods.
Read the Nutrition Facts labels of foods to see how many grams of fat the products you consume contain.
Read the Nutrition Facts label if you are unsure of how many fat or oil servings a certain amount of food contains.
