Your body is a complex machine that requires the right combination of fuels to keep it running at peak efficiency. You need sustained energy and stamina to meet the varied demands of college life. Good nutrition is essential to doing your best and getting the most out of your course work, studying, extracurricular activities, part-time job, and social life.
You are much more independent now than when you were in high school and living at home. But that independence brings with it new responsibilities in caring for yourself. With no one to tell you what and when to eat, it's important for you to know what your body needs for nourishment and to avoid the nutritional problems many students encounter.
Suzanne, for example, found it hard to resist the potato chips and nachos her roommate kept in constant supply. She started nibbling between meals and late at night. To keep up with her studies, she cut back on her swimming schedule and got much less exercise than when she lived at home. Whenever there was a paper to write or a test to study for, she would prepare herself with a snack-something she thought was healthy, like a granola bar or a frozen yogurt.
Because she was too busy to have lunch, she started eating bigger breakfasts-orange juice, bacon, sausage, eggs, hash browns, toast with butter and jam, and black coffee instead of the fruit juice, cereal, and skim milk she always ate at home. By dinnertime she was starved, and the cafeteria food looked good. She loved the fried chicken, and a helping or two from the salad bar seemed like a prudent alternative to the french fries.
Her friend Eric found himself in a similar pattern-putting a lot of time into keeping up with his course work, spending less time than before on sports and bike riding, eating at fast-food restaurants, skipping meals from time to time, and binging on candy bars as a substitute for lunch several times a week.
Before the semester was over, Eric's friends started teasing him about the spare tire around his waist, and Suzanne was having trouble zipping up clothes that fit her perfectly a couple of months earlier.
These problems are familiar and can be resolved. Here are the basic questions and answers about nutrition that can help you develop the good eating habits that will give you the nourishment you need and the energy you want while you maintain the right weight for your height and build.
Probably because of the number of calories you are consuming. Calories are the units used to measure the energy-producing value of food. They do not measure the nutritional value of food. Your body needs fuel (calories), but more important, your body needs the right types of fuel, just as a car engine requires the correct octane fuel or a boat engine has to have gasoline plus oil for it to run well. The body is a far more complicated machine than either a car or a boat, and essential to its efficient functioning are the kinds of fuel used to run it.
Calories come in three basic forms: protein, simple and complex carbohydrate, and fat. There are actually six classes of nutrients, although three have no calories. Each food has varying proportions of these six nutrients.
|Energy (calories per gram)|
We can see that fat is a very dense source of calories. Each teaspoonful of fat contains nearly two and one-half times the calories in a teaspoonful of protein or carbohydrate. A medium-sized baked potato, without butter or sour cream, has about 95 calories, all of them carbohydrates and protein. That same potato in the form of french fries contains 284 calories, and 119 of those calories are fat. Just 3.5 ounces of the potato chips Suzanne was snacking on contain 568 calories, 358 of them as fat!
It is easy to consume the same amount of food but, by changing the quality or fat content of the food, drastically increase your caloric intake and, in turn, gain weight.
There is a simple formula to determine what your ideal body weight (IBW) should be.
Once you know that weight, you can calculate the amount of fuel, or calories, needed to maintain it. A factor of plus or minus 10 percent in the following formulas considers different body types, muscle mass, and bone structure, so don't be too concerned if your body weight falls a little outside the given range. The general guidelines follow.
If you are a man, give yourself 106 pounds for the first 5 feet of height and an additional 6 pounds for each inch over 5 feet. For example, if you are 5 feet 10 inches, your body weight should be 106 plus 60, or 166 pounds. With the plus or minus 10 percent factor, the range is 149 to 183 pounds.
If you are a woman, give yourself 100 pounds for the first 5 feet of height and an additional 5 pounds for each inch over 5 feet. Subtract 5 pounds for each inch under 5 feet. For example, if you are 5 feet 6 inches, your body weight should be 100 plus 30, or 130 pounds. With the plus or minus 10 percent factor, the range is 117 to 143 pounds. Realize that most women in American society want to weigh 10 to 15 percent less than their ideal body weight. This can be a very unhealthy situation as we discuss in Eating Disorders.
If you find that your weight is more than 10 percent outside the recommended range, it would be a good idea to visit your doctor for a physical.
The number of calories you need is calculated by activity level as well as by body size. The basic daily energy, or caloric, requirement is determined by the basal metabolic rate (BMR) - the energy needed to sustain bodily functions (keeping warm, maintaining heart activity, making new cells, and so forth) in a resting state. Caloric requirements are largely genetically determined and generally range between 1,000 and 2,000 calories a day. However, with activity you burn more calories. Exercise increases the BMR. Chronic dieting decreases metabolic rate.
One of the causes of Suzanne's weight gain was her sedentary lifestyle. She no longer had her daily swim workouts to keep herself in shape and to burn calories more efficiently. The lack of exercise had reduced the amount of calories she burned while sitting and studying. In high school her body actually used calories more efficiently all day long because of her morning workouts. While performing the same activity (studying), she now expends fewer calories than she did a year ago.
To determine the correct calorie count for your individual needs, add your basal caloric needs to the calories required to support the physical activities you are involved in. Figuring your basal caloric needs is simple. Multiply your ideal body weight by 10 as shown in the following equation:
10 x _______ IBW _______ basal calories
Next, determine your activity level: sedentary, moderate, or strenuous. As a rule of thumb, light activity burns fewer than 200 calories per hour, moderate between 200 and 300 calories, and strenuous burns more than 350. For a sedentary lifestyle, such as Suzanne's and Eric's, in the next equation multiply the IBW by 3. For a moderate level of physical activity-light jogging, swimming, bike riding, lots of walking-multiply the IBW by 5. For strenuous physical activity for a minimum of 45 minutes a day four times a week, multiply the IBW by 10.
3, 5, or 10 x ________ IBW = ________ activity calories
Before you add the two figures, note that there's a bonus for those who exercise strenuously. We said that Suzanne's previous exercise program had helped her body burn calories more efficiently. Persons who exercise strenuously on a regular basis not only get more calories per pound of IBW; they also get to add calories for each minute of daily exercise. Running 45 minutes a day, four times a week, averages about 25 minutes of daily exercise. Women who qualify for the bonus can add 8 calories per minute of daily exercise. Men can add 10 calories per minute of daily exercise.
8 or 10 x ________ minutes of exercise = ________ training calories
Now add all the calories necessary to maintain your ideal body weight:
___________ basal calories
+__________ activity calories
+__________ training calories
=___________ total daily caloric needs
If you find that this number of calories seems high and would cause a weight gain, your metabolic rate may have decreased because of chronic dieting, frequent weight fluctuations, or fasting.
We mentioned earlier that calories come in three different forms: protein, complex and simple carbohydrate, and fat. All of these, in varying proportions, are necessary to good health. A balanced diet should contain the following percentages of your daily caloric intake:
Protein - 10 to 15 percent
Carbohydrate - 60 to 70 percent
Fat - 20 to 30 percent
Although protein can be used for energy, it is the least efficient source and is converted for fuel only if there are insufficient calories in the rest of the diet. Most Americans eat too much protein under the mistaken impression that it builds muscle. Muscle mass is increased only by exercising the muscle. Excess protein must be either converted to urea and excreted, a process that puts undue strain on the kidneys, or converted to fat and stored.
Protein comes from both animals and vegetables, although in the average American diet 60 to 80 percent comes from animals. The problem is that animal sources of protein are usually laden with generous portions of fat and cholesterol, both of which can contribute to heart disease. The fat is often hidden in poultry skin or embedded (marbled) in red meat and thus is hard to detect and remove.
Suzanne was eating plenty of protein with her bacon, sausage, and fried chicken, but she consumed a tremendous amount of calories as fat at the same time. At home they had always baked or broiled chicken after removing the skin, reducing the fat calories 50 percent simply by the method of cooking, while preserving the original protein source.
The components of protein are amino acids, which are essential to maintaining and developing muscle, bone, cartilage, blood, and skin. Of the 22 different amino acids, 14 can be synthesized by the body. The remaining 8 (for adults, 9 for infants), the so-called essential amino acids, cannot be made by the body and must be eaten on a regular basis. Protein from animal sources, which are called complete protein sources, is rich in these 8 essential amino acids.
If you restrict yourself to vegetable sources for protein, you are confronted with a different set of problems. Most vegetables are not complete protein sources, meaning they do not have all the essential amino acids and must be complemented with another protein source that supplies the missing amino acids. A diet of beans, for example, must be supplemented with rice, corn, wheat, or some other grain to supply your body with complete protein. Or you can combine a little fish, chicken, or meat with rice to get complete protein. Your body uses amino acids to build new cells, but it can only use the amino acids if all of the essential amino acids are there at the same time.
The average non athletic person can determine how much protein you need each day by multiplying your body weight by 0.4 (representing 0.4 grams of protein). Thus, an average 150-pound man needs approximately 60 grams of protein daily, which represents about 240 calories. This amount of protein is easily obtained in most diets that include even small servings of meat, fish, eggs, milk products, and beans.
If you are a strength athlete you need about 0.8 grams of protein per pound of bodyweight. Endurance athletes, doing more cardiovascular exercise than strength training, need 0.6 grams of protein per pound of bodyweight.
No. Excess protein (more than 1 gram per pound) cannot be used or stored in the body. Instead it is converted to fat or lost in the urine.Excess protein can be harmful to your health by overworking your kidneys, leading to dehydration and possible kidney damage. It can cause loss of calcium from your body and if the excess protein is from a high fat source - like red meat - you may be increasing your serum cholesterol and risk for heart disease.
Remember that eating extra protein does not mean your muscles will get larger. Eric mistakenly thought he was getting extra energy and strength for playing soccer by eating steak and hamburger before his workouts.
Carbohydrates are not fattening if you eat the appropriate kinds and amounts. Complex carbohydrates such as potatoes, pasta, corn, whole grains, and beans are often avoided because they are thought to be fattening, although nothing could be further from the truth. The butter, sour cream, and sauces we usually consume with them are fattening. Ounce for ounce, a T-bone steak contains five times the calories of a baked potato without the butter and the sour cream.
Carbohydrates are your body's main source of energy. They are the primary fuel for the brain and for muscular activity. Since they cannot be stored in large quantities, they need to be ingested at each meal, preferably in the form of complex carbohydrates.
There are two forms of carbohydrate-simple (sugars) and complex (starches). Sugars are easily broken down and enter the bloodstream quickly as glucose. Starches are more slowly broken down. Insulin, a hormone secreted by the pancreas, stores the extra glucose in cells in the form of glycogen. When the cells are saturated with glycogen (1,200 to 2,000 calories), the additional glucose is converted into fat. The rapid rise in glucose from simple carbohydrates induces a rapid release of insulin, which acts to clear the bloodstream of glucose and put the glucose into storage. The slower digestion of complex carbohydrates causes a slower release of insulin, less storage of glycogen and fat, and more available energy. Your body can store 1,200 to 2,000 calories of energy as glycogen in the muscles and the liver. This is the energy you use for your daily activities.
Because complex carbohydrates are absorbed much more slowly than simple carbohydrates, they are a better source of energy for the body. The cold cereals and oatmeal that Suzanne ate for breakfast at home were an ideal source of slow-burning energy to sustain her until lunchtime. Complex carbohydrate sources such as whole grains, fruits, and vegetables also contain large amounts of the vitamins and minerals needed by the body.
|Foods highest in complex carbohydrates||Lower carbohydrate choice|
|Spaghetti, noodles, macaroni||Pizza, lasagna with lots of cheese, meat|
|Rice, stuffing, potato, yams||French fries, fried rice, gravy|
|Lentils, chili beans, split peas||Casseroles with rich sauces and gravies|
|Bread, muffins, bagels||Doughnuts, buttery pastries|
|French toast, pancakes, cereal||Eggs|
|Jam, jelly, honey, syrup||Butter, margarine, cream cheese|
|Bananas, pineapple, raisins, dates||Pastries made with lots of butter|
|Apple crisp, date squares, fig newtons||Ice cream|
|Juices - apple, grape, apricot, orange||Beer, wine, alcohol|
|Blenderized fruit and juice||Milk shake|
|Sherbet, ice milk, yogurt||Chocolates, candy bars|
Complex carbohydrates are usually the main source of fiber as well. Fiber helps keep the bowels regular and is associated with reduced rates of colon, rectal, and breast cancer. Snacking on fiber-rich foods such as an apple, an orange, or a carrot will satisfy the appetite without causing surges in blood sugar; it will also provide much better nutrition than does a candy bar or a bag of potato chips. You should try to get 20 to 35 grams of fiber per day. There is more information on fiber in Preventive Medicine.
No, because that quick lift is followed by an equally sudden letdown. Simple carbohydrates, such as the sugar in candy bars, enter the bloodstream almost immediately, causing a very high level of glucose, or blood sugar. This fast rise in glucose stimulates the pancreas to secrete a great deal of insulin to process the excess glucose and put it in storage as glycogen or fat. As the glucose is stored, there is a rapid drop in the amount left in the bloodstream. This lowered blood sugar produces the "sugar blues," a feeling of depression or low energy experienced 20 to 60 minutes after the initial burst of energy released by eating candy or other sugary food.
Sugared breakfast cereals, as well as candy bars and sodas, contain large amounts of sugar and may generate these erratic swings in blood sugar. The insulin is looking for more sugar to process, and you feel the urge to eat another candy bar to cheer yourself up.
What's really happening is that your blood sugar levels are bouncing up and down instead of maintaining a steady level as they would if you regularly ate complex carbohydrates and protein. This would give you even levels of blood sugar by slowly releasing glucose into the bloodstream from storage as it is needed. Since blood sugar is the immediate fuel your brain uses, it is important to maintain a steady supply.
No, because all sugar forms are basically the same and are composed of various simple sugars such as fructose, sucrose, and glucose. Advertising claims to the contrary, all simple carbohydrates, or sugars, are handled exactly the same way by the body. And all sugars (honey, brown sugar, raw sugar, maple syrup, or jelly) have essentially no vitamins and only trace minerals in some (molasses) to go with their calories. The high caloric count and the lack of nutrients are why sugars are referred to as "empty calories."
Don't spend extra money on so-called natural sugars unless you enjoy their flavor. Your body doesn't know the difference, and there is no nutritional benefit.
When used in moderation, small amounts of sugar can add taste and enjoyment to foods. But most Americans eat too much sugar-a third of a pound a day, or 20 to 25 percent of the day's total calories. And excessive consumption of sugar is clearly related to obesity, tooth decay, and increased risk of developing diseases such as hypertension and diabetes.
Much of the sugar in your diet is hidden in soft drinks, candy, ice cream, frozen yogurt, cookies, sweetened granola, canned fruit, and sugared cereals. Read labels for sugar content.
Fructose, sucrose, glucose, maltose, and dextrose are all slightly different forms of sugar.
If sweets are a psychologically important part of your diet, try to decrease the amount. Cut down to one cookie a day rather than eating three or four cookies. Enjoy the natural sweetness of fruit or fruit juices; drink diet sodas or chew sugar-free gum to satisfy those cravings. Small amounts of an artificial sweetener rather than sugar in your coffee can help. Cinnamon, ginger, cloves, allspice, and vanilla as well as unsweetened apple juice can be used as flavorings to replace the sweetness of sugar. Some cereals with less than 8 percent sugar are shredded wheat, puffed cereals, Nutri-Grain, Wheat Chex, Grape-Nuts, Rice Krispies, Cheerios, Special K, cornflakes, regular oatmeal, and Wheatena.
When Eric turned to what he thought were quick-energy foods, like candy bars for lunch, he was in danger of becoming a junk-food junkie-riding the blood sugar roller coaster while consuming a large number of calories with almost no nutrients. When he was home for the holiday break, Eric's sister, who is in medical school, pointed out the problems with his diet. When he switched to complex carbohydrates and small, frequent snacks of fruit, bread, and muffins, his weight started to drop and he had enough energy to perform much better when he played soccer. He lost some of the craving for sweets and could enjoy a little dessert at night without feeling guilty or gaining extra weight.
Two of the three artificial sweeteners approved for use in the United States have been linked to cancer in laboratory animals fed many times the amount human beings would consume. One, cyclamate, was banned in 1969 because of this finding. The other, saccharin, is still in use today. Saccharin has been linked to bladder cancer in women, particularly those who smoke, but the findings are inconclusive.
Aspartame, also known by its trade name Nutrasweet, was approved for use as an artificial sweetener in 1981. It is a combination of two amino acids the body digests as it does other proteins. One of the amino acids - phenylalanine - cannot be metabolized by people with a disease called phenylketonuria (PKU). This is the reason for the warning on cans of diet soda. There is at present no scientific evidence of any side effects associated with the consumption of aspartame, although there have been some anecdotal reports of headache, depression, dizziness, blurred vision, and confusion in some persons. If you experience any of these symptoms, it may be a good idea to limit your intake of artificial sweeteners by consuming no more than one or two diet sodas a day.
The average American diet contains 40 to 60 percent fat, which is far too much. There are many health consequences of too much dietary fat. Being overweight puts an additional strain on the heart and makes it harder for the heart to pump blood through the body. Animal fats contain cholesterol, a waxy chemical that is deposited in the arteries and may eventually clog them. This condition, called arteriosclerosis, is the main cause of death from heart disease.
One tablespoonful of polyunsaturated oil daily meets your nutritional needs. This provides all the essential fatty acid necessary to absorb the fat-soluble vitamins you require. Suzanne was consuming many times this amount. Fat is the most concentrated source of calories. Each gram of fat contains 2.4 times more calories than does a gram of protein or carbohydrate.
Each strip of bacon in Suzanne's breakfast had 48 calories, about 40 of them fat. Each link of sausage had nearly 250 calories, over 200 in the form of fat. A breakfast of meat, scrambled eggs, hash browns fried in butter, toast with butter and jam, orange juice, and the occasional sweet roll contains over 1,200 calories, more than half of them fat. In the first hours of the day, Suzanne consumed 75 percent of the calories needed to maintain her ideal body weight of 120 pounds, and half of those calories were fat. A high percentage of the fat you eat is not readily apparent in such foods as processed meats, some cheeses, regular yogurt, nuts commercially prepared cakes and cookies, and even such fruits as avocado, coconut, and olives, which are more than 75 percent fat.
Fast foods are also very high in fat. A Kentucky Fried Chicken snack box, for example, contains over 400 calories, half of them fat. An Egg McMuffin (352 calories), a Filet-O-Fish (415 calories), or a Quarter Pounder with cheese (518 calories) from McDonald's all derive more than half their calories from fat. Try the hidden-fat test: put some cookies or a packaged muffin or a cupcake on a paper napkin for 20 minutes and see the ring of grease that forms.
Eric's favorite fast-food meal was two Big Macs, an order of fries, a large Coke, and a piece of cherry pie for dessert-nearly 1,600 calories, more than 700 of them as fat. A typical fast-food restaurant meal is also very high in sodium, or salt.
Eating a heavy, fat-laden meal before class can leave you drowsy during the lecture, and not because of boredom. Fat is harder to digest and therefore stays in the digestive tract longer, causing the body to divert the blood supply from the brain and making you sleepy. Suzanne drank black coffee with her heavy breakfast to help stay alert through her tough chemistry class. That class may have been tougher for her because of the preceding meal. Generally, it's not a good idea to eat a heavy meal right before an exam or an exercise session. Rely on complex carbohydrates to give you sustained energy during the day.
Are there different kinds of fats as there are different kinds of carbohydrates?
The four dietary fats are cholesterol and three forms of fatty acids-saturated, monounsaturated, and polyunsaturated. Cholesterol and saturated fat have been found to contribute to the formation of plaque on the lining of arteries, the condition called arteriosclerosis, which was discussed above. Cholesterol is not a necessary nutrient because the liver is able to synthesize it, and high cholesterol levels in the bloodstream indicate an increased risk of heart disease. Cholesterol in the diet comes only from animal sources such as egg yolks, meat, milk, and butter.
Saturated fats, such as lard, animal fat, and coconut oil, tend to be denser and are solid at room temperature, whereas unsaturated fats are liquid. Saturated fats tend to raise the level of blood cholesterol because they are a precursor to the body's synthesis of cholesterol. Unfortunately, manufacturers of many baked goods like crackers, cookies, and muffins use highly saturated palm oil and coconut oil because they are less expensive ingredients.
Fat from plant sources is usually a mixture of the three types of fatty acids, with one type predominating. Polyunsaturated fats may help remove some of the cholesterol from the body, allowing it to be excreted in the feces. Monounsaturated fats seem to be neutral regarding the amount of cholesterol in the bloodstream, although some experts think this form of fat may decrease arteriosclerosis.
Researchers have found a strong link between a high-cholesterol, high-fat diet and heart disease and cancer. To improve your diet, reduce all fats, replacing some of the saturated fats with polyunsaturated fats. Studies have even indicated a link between cancer and a diet high in polyunsaturated fats.
This dietary change may not seem too important to you now. It is hoped that you are not overweight and that you are 40 or 50 years away from worrying about a heart attack. With a poor diet, however, you may involuntarily cut that time in half. People do have heart attacks in their thirties and forties, not necessarily as a result of a poor diet, but it can certainly be a contributing factor.
If you have a family history of heart disease, it is a good idea to go to a medical clinic for a blood test to measure your serum cholesterol. This measurement can be a good predictor of your risk of future heart disease. See Preventive Medicine for more information on lowering your risk of heart problems.
How can I tell what type of fat is in something I eat? Is a so-called no-cholesterol food a food with no fat?
Many foods now carry labels saying "no cholesterol," but a closer inspection of the label will reveal the presence of other fats. If the manufacturer has substituted margarine (made from vegetable oils) for butter, the amount of fat calories in the product remains the same.
All animal fats contain cholesterol and are usually high in their proportion of saturated fat. While vegetable fats have no cholesterol, they may have a high amount of saturated fats, which can contribute to heart disease. Knowing the type of oil used can tell you the amount of saturated fat you are eating. For example, palm oil is often used in canned and fried foods as well as in baked goods. Of the calories in palm oil, 51 percent are saturated fat, 39 percent are monounsaturated fat, and 10 percent are polyunsaturated. Coconut oil, another inexpensive oil used often in baked goods, has a higher percentage of saturated fat than lard does. Over 90 percent of the calories in coconut oil are saturated fats. Corn oil, safflower oil, and sunflower oil, on the other hand, are all vegetable fats that are high in polyunsaturates. By reading the labels on the products you buy, you can usually determine what oils have been used in the processing.
The food labels I have seen usually list the amount of fat in grams. How can I tell what percentage of that food is fat?
There are 9 calories per gram of fat. Multiply the listed grams of fat by 9, and divide that figure by the total overall calories to find the percentage of fat in that product. Sometimes there is a nutritive analysis as well as a list of ingredients on a package; this will tell you the amount of cholesterol and saturated and polyunsaturated fats. Limit your intake of saturated fats and cholesterol.
Is acne caused by the greasy foods and chocolate we eat?
Contrary to popular belief, acne is not caused by diet. It is perhaps one of the most embarrassing, widespread, and misunderstood problems of young people. Acne may develop when the body starts producing hormones called androgens (in both men and women) during puberty. The problem is almost completely hereditary, and diet has very little or nothing to do with it. If some individuals think that particular foods seem to trigger an outbreak of acne, they may want to avoid those foods. We will talk further about the cause and treatment of acne in Common Medical Problems. In the meantime it's safe to blame your parents for acne, but they couldn't help it either.
I keep hearing bad things about salt. Should I be concerned?
Salt (sodium chloride) can be harmful for some people if used to excess. Most Americans eat more than enough salt, up to 20 or 30 times the amount necessary to replace the daily loss of 0.2 grams. One teaspoonful of salt contains 2.3 grams of sodium. The only reason we ingest all this extra salt is because our taste buds are used to it.
Excessive salt in the diet can lead to high blood pressure, or hypertension, in salt-sensitive people. Hypertension is a disease with no noticeable symptoms until serious damage may have occurred. It can eventually lead to kidney damage, stroke, or heart disease. If you have been told your blood pressure is elevated, avoid adding salt to your food. There is plenty of salt in a balanced diet, even for someone who is exercising heavily.
Here are some hints to gradually decrease your use of salt:
Besides popcorn, plain baked potatoes, and apples, is there something else out there that's good to eat?
The variety of healthful foods is almost unlimited. What is important is to eat them in balance. Balance comes from getting adequate amounts of protein, carbohydrate, and fat in proper combination to ensure absorption and utilization of these nutrients. The United States Department of Agriculture developed a food pyramid to help us determine a well rounded diet.
The salad bar is an excellent source for vegetables. Unfortunately, the macaroni salad and potato salad are heavily laden with mayonnaise, which contains 100 calories per tablespoon, 98 of them fat. In addition to the lettuce, tomatoes, and onion in her salad, Suzanne threw on a scoop of three-bean salad and covered it all with some of her favorite blue cheese dressing; each tablespoonful of the dressing contains 71 calories, 65 of them fat. Grazing at a salad bar, because of the usually unlimited quantities available as well as the fat content of most dressings, can be a high-calorie operation. That innocent-looking plate of salad, a buttered roll, and a glass of milk contain nearly 1,000 calories. Twice through the salad bar, and Suzanne would have consumed over 1,600 calories while thinking she was eating only a "nonfattening" salad.
Eric had a similar problem with his fast-food and high-sugar diet. Proportionately, the fat content of his diet was over 50 percent. The carbohydrates he was consuming are mainly simple carbohydrates with questionable nutritive qualities (Coca-Cola, candy bars), or they are complex carbohydrates (hamburger buns, french fries) that are hiding a great deal of fat. Because he was not eating enough complex carbohydrates as fruits, vegetables, and grains, his diet was out of balance.
How do I know if I'm getting all the vitamins and minerals I need?
Eating a balanced diet regularly will give you the necessary vitamins and minerals. Food supplements certainly can play an important role in a diet that is deficient in certain areas, but a dependence on vitamin pills to fulfill nutritional requirements can be an expensive, an unnecessary, and a possibly dangerous way to go.
Taking a multiple vitamin or some extra vitamin C certainly isn't going to do you any harm, except in the pocketbook, but counting on a handful of pills to make up for poor nutrition may. Excess amounts of any supplement, but especially vitamins A, B6, D, and E and iron, can have very detrimental effects on your health, including kidney, liver, nerve, and heart damage. Consuming excessive amounts of those nutrients in the food you eat would be next to impossible.
When Suzanne showed up at the student health center complaining of fatigue, she had already started taking a multiple vitamin, thinking it might help. A routine blood test showed her to be anemic. You may wonder how she could be eating that much protein and still be anemic, but this condition is quite common among menstruating women.
The cause of her anemia was a lack of iron in her diet, not a lack of protein or vitamins. Women need 18 milligrams of iron daily, nearly twice as much as men require. Suzanne could meet her daily requirement of iron by eating a bowl of iron-fortified cereal. However, now that her iron store was depleted, eating only the daily requirement of iron would not allow her to catch up, and it was necessary for her to take supplements. Taking iron supplements is best done under a doctor's supervision. Your doctor can determine if you are anemic and, if so, the cause. He or she can tell you what type of iron and how much you need to take and also how long you should take it.
Other ways to increase iron in your diet include cooking in cast iron pans (especially tomato sauces); combining iron-rich foods with foods that are rich in vitamin C (for example, an iron-fortified cereal and orange juice, and meat in tomato sauce for pasta); and avoiding black tea, which contains tannic acid, a substance that blocks the body's absorption of iron.
Along with iron, women need to be sure they are getting enough calcium. Menstruating women need 1,000 milligrams a day, or about the amount of calcium in three dairy servings. Women who have stopped having periods need more calcium-1,500 milligrams, or about five dairy servings daily. Calcium is needed to ensure bone and muscle growth and to prevent osteoporosis. It is best absorbed from food sources.
Consult your doctor for your specific calcium requirement. If you are unable to get the required calcium from your diet, your doctor may choose to recommend calcium supplements. Be sure to follow his or her instructions carefully.
The National Academy of Sciences has published the Recommended Dietary Allowances (RDA), guidelines for the amounts of nutrients needed daily in the diet of a healthy person during different stages of life. The requirements for an adolescent still going through the development of height, bone, and muscle are different from those of a more sedentary adult.
These guidelines are used in labeling food and vitamin/mineral supplements. Although in general each meal should provide one-quarter to one-third of a day's needs, the RDA requirements are intended to be met by balanced meals over the period of a week. This does not mean supplementing poorly planned food choices by taking a vitamin pill. Nor does it mean that portions need to be measured, counted, and analyzed for their specific amount of each nutrient.
Your food should have variety. Eating the same foods all the time or limiting the types of food you eat may mean you are not getting necessary trace minerals, for which RDA amounts are not yet determined. A variety of foods ensures a variety of nutrients.
It's important, too, for you to enjoy the foods you are eating. The wide range of individual food preferences, based perhaps on culture and geographic region, should be reflected in your diet.
What diet should I adopt to gain or lose weight?
Dozens of books are devoted to very strict diets for weight loss, and a few deal with weight gain. Many of these diets have no scientific basis, and some can be extremely dangerous. Too often we think of a diet as a means to an end. "When I lose ten pounds, I can go off my diet." This usually entails a radical departure from ordinary nutrition rules and a great variation in caloric intake. Such "diets" are generally unsuccessful and can result in a loss of lean body mass (muscle) instead of fat and in a lowered metabolic rate.
A single pound of body weight represents 3,600 calories. Your body is designed to gain or lose weight slowly. You can meet a weight goal by increasing or decreasing your calories by 400 to 800 calories a day, depending on your size. To find out if you need to gain or lose weight, check your ideal body weight range (see page 6). If there is a discrepancy, you can have a body fat evaluation. Either skinfold measurements or underwater weighing can determine your body fat within 2 to 8 percent accuracy. The average college-age male has 14 to 20 percent body fat, while the average college-age female has 20 to 26 percent body fat. An extremely active person, such as a marathon runner, may reduce these averages by half.
Women have less muscle and bone and more body fat than men do. Muscle tissue weighs more than fat. This explains the phenomenon of losing inches but not pounds through exercise. In the determination of desirable weight, all of these factors are considered together. Be sure that any weight goal you have in mind is objective and realistic. Many eating disorders, such as anorexia, bulimia, and obesity, are the result of unrealistic expectations.
Instead of going on and off a diet, try to maintain a steady caloric intake. If you need to lose weight, reduce your calories slightly-preferably the fats-and look for a gradual reduction in your body weight. Effective weight loss occurs slowly, 1/2 to 1 pound a week, and is best achieved by a combination of exercise and calorie reduction. If you lose 1 or 2 pounds a month, this means a weight reduction of 12 to 24 pounds in a year.
You will be much more likely to maintain a gradual weight loss than if you lose weight abruptly. If you need to gain weight, simply increase your calories, preferably in the form of complex carbohydrates. In either endeavor, increasing the amount of exercise will make it that much easier for you to reach your goals. For more information, see Exercise.
Researchers have found that taste appeal is a major factor in whether a diet is followed. If you are on a diet, eat what you like, within the guidelines of good nutrition. Select foods that are wholesome. Food that is lightly processed or unprocessed contains more of the original nutrients, fewer preservatives and additives, and less hidden fat or salt.
This means choosing whole grains such as unprocessed brown rice instead of instant white rice; a baked potato with a little cottage cheese rather than sour cream and butter-instead of french fries; and fresh peaches instead of canned peaches in syrup. If you are unsuccessful in reaching your weight goal, seek help from a registered dietitian (R.D.) or from your student health service.
Good nutritional habits and a balanced diet aren't developed in one day, nor are they destroyed in one unbalanced meal. Healthful eating means a lifestyle of making choices and decisions, planning, and knowing how to make quick and wise choices when you haven't planned.
What you learn about eating in these first years on your own will help establish good dietary patterns for the rest of your life. Making the break from home cooking and becoming responsible for choosing the foods you eat is part of the challenge of becoming a mature and an independent adult.
It is a challenge that should not be taken lightly. The nutritional habits you develop now will be difficult to change in the coming years when your body stops growing and your lifestyle may become more sedentary. Learning to make sensible choices from a confusing array of options is not easy, but the rewards are great. Eating nutritious and healthful food while maintaining your proper body weight will contribute to a better performance in the classroom, in the gym, and on the dance floor. You will feel and look your best.
In contrast, a poor diet can lead to insidious health problems that can interfere with success in academic and social performance and may eventually mean confronting a serious long-term illness, such as heart disease or diabetes. Knowing how much and what to eat is important knowledge.