Understanding Foods

The news is always filled with stories about diet and nutrition. Many of these stories make it hard for people to know what they should and should not be eating. According to the American Heart Association (AHA), there is no single recommended diet. Instead, the AHA has a set of guidelines that take into account that people need a variety of foods to eat and that some people have specific health problems, which could mean eating less of certain foods. If you think that you are not eating a well-balanced diet, if you have health problems, or if you are about to make major changes to your diet, talk to your doctor or a dietitian who can help you decide on a nutrition plan that works for you.

The US Department of Agriculture (USDA) and the Department of Health and Human Services have revised their guidelines for healthy eating. The new guidelines, called the 2010 Dietary Guidelines for Americans, focus on balancing calories with physical activity, and encourage you to eat more vegetables, fruits, whole grains, fat-free and low-fat dairy products, and seafood. They also urge you to eat less sodium, saturated and trans fats, added sugars, and refined grains.

Carbohydrates

Carbohydrates are the main source of fuel in a balanced diet. The body converts carbohydrates to "glucose," which is a type of sugar. Your body uses some of this glucose right away for energy, and any extra glucose is converted into a sugar called "glycogen." Your body stores glycogen in your liver and muscles for future use. Glycogen can be quickly changed back to glucose as needed. Once your body has made enough glycogen, the leftover glucose is stored as fat.

Sugars and starches are carbohydrates. Sugars are called "simple carbohydrates" or "simple sugars." The most common form of simple sugar is glucose. When glucose molecules link together, they create a number of larger molecules called "complex carbohydrates." Starches and fiber are examples of complex carbohydrates.

Most carbohydrates are in the form of starches, which are found in foods such as grains, potatoes, and other starchy vegetables. Another common source of starch in our diets is refined grains, like white bread and pasta. Starches also may be added to foods to thicken or stabilize them. Added sugars and added starches usually increase the calorie count of foods, but they do not add essential nutrients. Although most people consume an adequate amount of total carbohydrates, many people consume too much added sugar and refined grain and not enough fiber.

Sugars

Sugars, or simple carbohydrates, give the body a quick source of energy, because they can be used right away. Refined and brown sugars, syrups, and honey are examples of sugars. Added sugars are those found in foods like candy and soft drinks, but they add more calories than nutrients to your diet. According to the 2010 Dietary Guidelines for Americans, you should reduce the number of calories you get from added sugars. Instead, you should try to get your daily supply of sugars from fresh fruits, which will also add vitamins and minerals to your diet.

Starches

Starches are called complex carbohydrates because your body must break them down to use their sugars. Breads, cereals, corn, peas, potatoes, pasta, and rice are examples of complex carbohydrates. Many studies have shown that people who eat a lot of whole grains have a lower risk of coronary artery disease than people who mainly eat high-fat or high-sugar foods do.

Fiber

Fiber is another form of complex carbohydrate. A diet high in fiber has been shown to reduce cholesterol levels and help protect against heart disease, cancer, and stomach and bowel problems. Fiber comes in two forms: insoluble and soluble. Insoluble fiber can be found in cereals, whole-grain breads, rice, and many vegetables. Soluble fiber is found in oatmeal, dried beans, peas, and many fruits, including apples, strawberries, and citrus fruits.

The new dietary guidelines recommend eating 14 grams of fiber per 1,000 calories, or 25 grams per day for women and 38 grams per day for men. You should try to eat foods that contain both insoluble and soluble fiber. Both forms are important to your diet. A diet high in soluble fiber may lower your risk of heart disease by decreasing your blood cholesterol. Insoluble fiber helps speed the passage of food through your digestive tract, keeping your body "regular." Eating fiber-rich foods may also help you lose or control your weight because most high-fiber foods provide complex carbohydrates, protein, vitamins, and minerals with little, if any, fat. Also, fiber takes up more space in your stomach and digestive tract than fats and simple sugars do, so you may feel full without eating as many calories.


Proteins

Proteins give your body the building materials for the growth, maintenance, and repair of tissues and muscles. Proteins also help your body make hormones. Extra protein is converted and stored in your body as fat, which can be used as emergency fuel when carbohydrates and fats are not on hand.

There are two main types of protein: animal protein and vegetable protein. Foods rich in animal protein include beef, pork, fish, chicken, eggs, and dairy products. Some foods that contain vegetable protein are broccoli, lentils, potatoes, pasta, oatmeal, rice, nuts, chickpeas (garbanzo beans), soybeans, and kidney, lima, and navy beans.

Although animal products are a good source of protein, eating a lot of animal products can raise your cholesterol level since animal products are often high in cholesterol and saturated fat.

The new dietary guidelines suggest that we should eat more protein in the form of seafood. Seafood contributes a range of nutrients, notably the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Studies have shown that eating about 8 ounces of seafood per week is associated with reduced number of heart-related deaths among people with and without heart disease.

Fats

The American Heart Association’s diet allows 30% of your daily calorie intake to come from fat. A Mediterranean-style diet may allow for up to 40% of your daily calorie intake to come from fat, but that extra 10% must come from healthy fats like olive oil, avocado, and fish.


Dietary fat is an important part of your daily nutrition, but you only need a small amount to keep your body's chemistry in balance.


Dietary fat comes in 2 basic forms: saturated and unsaturated. Saturated fat is the type of fat that raises your cholesterol and increases your risk of heart disease. Main sources of saturated fat are the butter fat in milk products, fat from red meat, and tropical oils such as coconut oil.

Unsaturated fat is better for you. It comes in 2 forms: monounsaturated or polyunsaturated. Vegetable oils are the best-known sources of unsaturated fat. Keep in mind, though, that a "100% vegetable oil" product may not live up to its name. Hydrogenation, the process that turns liquid vegetable oil into hydrogenated or partially hydrogenated vegetable oil to make shortening, margarine, and other solids, turns unsaturated fatty acids into saturated fatty acids. In general, you can easily recognize saturated fats because they will be solid at room temperature. Think of butter, stick margarine, shortening, and coconut oil. On the other hand, olive oil, canola oil, peanut oil, and liquid margarine are liquid at room temperature because they contain mainly unsaturated fat.

Another good way to tell whether a fat is saturated or unsaturated is to look at the label. Food manufacturers are required to list saturated fat separately, so this type of unhealthy fat is easy to spot.

In addition to saturated fat, the hydrogenation process creates another kind of unhealthy fat: trans fatty acids. This type of fat is also listed on food labels. Trans fatty acids are made when unsaturated vegetable oils are hydrogenated. The unsaturated fatty acids that do not become fully saturated may instead become trans fatty acids, which also may contribute to heart disease. Trans fatty acids have been shown to lower levels of "good cholesterol" and raise levels of "bad cholesterol."

In general, you can lower your trans fatty acid intake by avoiding foods that contain ingredients such as margarine, shortening, and hydrogenated or partially hydrogenated oils. Also, you can avoid foods such as french fries, doughnuts, cookies, and crackers, which are often high in trans fatty acids as well as saturated fat. Since trans fatty acids rarely occur naturally, they are mostly found in processed foods made with hydrogenated vegetable oil.