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How Diet Affects Your Health

You Are What You Eat!

To a certain extent you are indeed what you eat. Generally speaking, if you eat too much of an unhealthy food, your body fights back in the form of disease. For example, if you eat too much fat you gain weight and put yourself at risk for heart disease, stroke, and some forms of cancer. On the other hand, high-fiber foods such as vegetables, fruits, and whole grains may help lower the risk of certain cancers and heart disease.


The diet-related diseases and disorders you face today are:

Heart Disease
Liver Disease and Cirrhosis
Regulation of the Body's Immune System

Diet is not the only factor that causes these diseases. But changing your diet for the better reduces the chances that these diseases will affect you.


Most people think heart disease is primarily for men. In fact, heart disease is the major cause of death in American women, killing more women every year than all types of cancer combined. A woman who has a heart attack is twice as likely as a man to die of it, often because it is diagnosed at a later stage in the disease, when fewer treatment options are successful. Heart disease affects women about 10 years later than men, usually after menopause.

A stroke (damage to brain tissue caused by blockage or leaking of a blood vessel) results from many of the same problems that cause heart disease. Atheroscierosis (the buildup of fatty deposits in artery walls) and high blood pressure are related to both heart disease and stroke.

Fat and heart disease:

Too much saturated fat and cholesterol in the diet and obesity (being 20% or more over your ideal weight) are the major contributors to a high total cholesterol level, which is a major risk factor for heart disease. Foods that are high in saturated fat (the kind found in red meat and whole-milk products) raise your cholesterol much more than foods that are high in cholesterol.

These harmful dietary fats (and obesity) increase the level of low-density lipoprotein (LDL), the "bad" cholesterol that streaks the inside walls of arteries with fat. This buildup of fatty deposits causes a narrowing of the blood vessels, which sets the stage for a heart attack or stroke. For every 1% increase in your total cholesterol level, your risk of heart attack increases 2% to 3%.

Obesity is a major cause of high blood pressure, which is a powerful risk factor for heart disease and stroke. Losing weight and exercising regularly can reduce your blood pressure and increase your level of "good" HDL, cholesterol. HDL, cholesterol protects against heart disease by mopping up harmful LDL cholesterol in the bloodstream and carrying it back to the liver, which breaks it down and eliminates it.

Fiber and heart disease:

Some forms of soluble fiber-such as that found in oatmeal, oat bran, barley, and dried beans-can help lower your cholesterol level and reduce your risk of heart disease and stroke.

Insoluble fiber, the type found in whole-wheat breads and many bran cereals, does not have the same cholesterol-lowering effect. But you should still eat both types of fiber-insoluble fiber for keeping your lower digestive tract running smoothly and soluble fiber for reducing your total cholesterol level.

Antioxidants and heart disease:

Although reducing fat has long been thought to be the most important component of a heart-healthy diet, eating lots of fruit and vegetables also provide protection against heart disease. Especially important are those fruits and vegetables that contain antioxidant vitamins and other nutrients.

Antioxidants help protect your body from molecules called free radicals, which are by-products of the body's normal chemical processes. Oxygen free radicals lack an essential component called an electron. They become harmful when they steal an electron from another molecule in the body, causing damage to cells and the cells genetic material. This process, called oxidation, is the same process that causes your car to rust. Damage from free radicals contributes to a variety of disorders-including heart disease, stroke, cancer, and cataracts-as well as the aging process.

Vitamin E is an antioxidant that may help prevent heart disease. The vitamin neutralizes free radicals and prevents them from damaging LDL cholesterol, the "bad" cholesterol. This free radical damage to LDL is what causes it to build up on artery walls.

The roles of other antioxidants-such as vitamin A and C, and beta carotene-in protecting against heart disease are being investigated.

Alcohol and heart disease:

If you don't drink alcohol, don't start now. Although studies have shown that moderate alcohol consumption may be associated with a lower overall death rate from diseases of the heart and blood vessels, no one recommends using alcohol as a means of preventing heart disease. The risk of alcohol addiction is too high. Alcohol is also high in "empty calories"--it has very little nutritional value.

However, drinking a moderate amount of alcohol (no more than two drinks a day) may provide some health benefits. A moderate amount of alcohol raises the level of high-density lipoprotein (HDL), the "good" cholesterol in the blood. Alcohol also reduces the blood's tendency to clot, lowering the risk that a blood clot in an artery will cause a heart attack. For the same reason, moderate drinking may also help prevent the most common kind of stroke--ishemic stroke--which is caused by blockage of an artery in the brain.

Sodium and heart disease:

Your risk of developing high blood pressure has a lot to do with your genes. Environmental factors, including your diet, play an important role as well.

Individuals vary widely in their responses to sodium. Blood pressure in some people is strongly influenced by the amount of sodium thay eat, while, in others, sodium seems to have no effect. Even among the people who already have high blood pressure, only about half appear to be sensitive to sodium.

Dispite the variability in blood pressure response to sodium intake, many experts recommend that all people limit the sodium in their diet to less than 2,400 milligrams per day (the equivalent of one teaspoon of table salt). Most people get more than 10 times the amount their body requires. Read labels when buying processed foods such as soups and sauces. Many contain excessive amounts of sodium. Other high-sodium foods include pickels, catsup, lunch meats, soy sauce, and monosodium glutamate (MSG),


Your genetic makeup can make you susceptible to some kinds of cancer, but how you eat can play a major role in increasing or reducing your risk of cancer. Research studies consistently show a relationship between a high-fat diet and cancer, particularly for colon cancer and prostate cancer. A high-salt diet has been linked to an increased risk of cancers of the stomach and esophagus.

The strongest link between diet and cancer is between a low-fiber diet and cancers of the colon and rectum. Fiber protects against cancer by adding bulk to stool, helping it retain water and speeding its movement through the colon. These processes work together to dilute any cancer-causing substances that may be present in the colon and reduce their contact with the wall of the colon.

It now appears that eating lots of fruits and vegetables can help prevent many kinds of cancer, including cancers of the lung, pancreas, colon, stomach, mouth and breast. A diet rich in fruits and vegetables is associated with a lower risk of lung cancer. It is not yet known whether the protective effect comes from fiber or other substances in the vegetables or from the replacement of higher-fat foods in the diet.

Fat and cancer:

The association between diet and colon cancer is clear. Eating a diet low in fat and high in fiber can reduce your risk of colon cancer. By-products of fat digestion may stimulate the development of polyps, which are tiny growths in the intestine that can become cancerous. A substance inherent in fat itself may also contribute to cancer. Saturated fat--the kind found in red meat, butter, cheese, and other whole-milk products; eggs; and tropical oils such as coconut and palm oils used in many commercially baked goods--is the most harmful kind.

The exact causes of breast cancer are not yet known. Breast cancer probably results from the interaction of a woman's genetic susceptibility and her diet and other environmental factors. A low-fat, high-fiber diet, which is linked to prevention of other cancers, appears to provide some protection against cancer as well. Eating lots of fruits and vegetables and other fiber-rich foods such as whole grains to replace fat in your diet can help reduce your risk of breast cancer.

Antioxidants and cancer:

Amomg the substances in fruits and vegetables that have a protective effect against cancer are antioxidants, which include vitamin A, C, and E and beta carotene. People whose diets are rich in antioxidants-containing foods have a lower incidence of most types of cancer, including cancers of the lung, cervix, colon, and stomach. Antioxidants are thought to protect against cancer by slowing the formation of molecules called oxygen free redicals that can damage the genetic material inside cells. Over time, this damage can trigger the development of cancer.

The antioxidant vitamin A and beta carotene (which is converted into vitamin A in the body) are abundant in dark-green and yellow vegetables such as sweet potatoes, carrots, and spinach. These foods may also contain related cancer-fighting substances that you cannot get from vitamin supplements.

Vitamin E and C may play a protective role against cancer by boosting your immune system, rallying its defenses against cancer. The vitamins may also prevent nitrites (chemicals used to preserve food) from turning into cancer-causing substances inside the stomach.

If you can, it is probably best to get your daily supply of antioxidants from the food you eat rather than from vitamin supplements. Eating lots of fruits and vegetables increases your intake of fiber and probably reduces your consumption of fat. A high-fiber, low-fat diet is known to reduce your risk of cancer.

Fiber and cancer:

A high-fiber diet may protect against several forms of cancer, particularly colon cancer. A number of factors may contribute to this protective effect. By speeding food through the intestines, fiber reduces the time the intestinal lining is exposed to any cancer-causing substances (carcinogens) that may be present in the food. Fiber attracts water to the stool, which dilutes the carcinogens and reduces their cancer-causing potential. Fiber may also alter the normal bacteria and acidity in the digestive system, reducing the production of carcinogens.

It may be that fiber does not protect against cancer, but high-fiber foods may replace less healthful high-fat foods in your diet. Other substances in high-fiber foods may be beneficial. Many doctors recommend that people who are at high risk for colon cancer increase their daily fiber intake to at least 35 grams a day.

Alcohol and cancer:

Alcohol intake increases the risk of some cancers. Alcohol may damage the genetic material inside cells and cause changes that can lead to cancer. Long-term heavy drinking increases the risk of liver cancer. There is a direct link between drinking and cancers of the mouth, throat, esophagus, and larynx, especially when combined with cigarette smoking. Alcohol and smoking work together to increase a person's risk of these cancers.


Maintaining a healthy weight can significantly reduce your risk of type II diabetes. (There is no known way to prevent the other form of the disease--type I diabetes.) For people who are diagnosed with type II diabetes, weight loss is often the first treatment that doctors recommend.

Because heart attacks are the leading cause of death in people who have diabetes, doctors recommend that people with the disease reduce their fat intake. If you are diagnosed with either form of diabetes, your doctor (often working with a dietician) will design a meal plan to fit your needs. Carefully following your recommended eating program can help you control the level of sugar in your blood and reduce your risk of long-term complications.


Your liver plays an extremely important role in your body--it absorbs fats, makes proteins, stores and releases energy, and eliminates harmful substances. Alcohol can cause severe damage to your liver. Excessive consumption of alcohol can cause three different kinds of liver disease--fatty liver, alcoholic hepatitis, and cirrhosis of the liver.

Most heavy drinkers develop a fatty liver, in which the liver becomes enlarged and engorged with fat. Stopping drinking can reverse this process. In alcoholic hepatitis, the liver becomes inflamed and tender, causing fever, fatigue, and jaundice (yellowing of the skin and whites of the eyes). In many cases, alcoholic hepatitis can be cured by quitting drinking.

The most devastating, potentially fatal, alcohol-induced liver disease is cirrhosis, in which the liver becomes scarred. This damage to the liver is permanent. Although quitting drinking cannot reverse the liver damage from cirrhos, it can prevent further damage.


Vitamin B6 and C and the mineral zinc play a role in regulating the immune system. Some vitamins may help boost the immune system and fight off the disease. Vitamins E, A, and C and beta carotene are antioxidants--they protect against the effects of cell-damaging molecules called oxygen free radicals.This damage to cells can lead to cancer. Because few Americans are eating even the minimum recommended sevings of fruits and vegetables each day, many doctors recommend a daily multivitamin/mineral supplement. This is especially important for older people, who tend to eat less and, therefore, get fewer nutrients. Food is still the better source of nutrients because it gives you more nutrition than a multivitamin/mineral supplement. Food has fiber, carbohydrates, and proteins.


Yes, your diet does affect your chances of developing osteoporosis (weak, thin, and brittle bones). Not getting adequate calcium and vitamin D in your diet can lead to osteoporosis. Calcium is a mineral that is deposited in your bones, giving the bones their strength and density. Most of your body's calcium is stored in your bones. When a person is not getting an adequate calcium supply, the body will take the calcium from the bones and use it.

The average American woman does not have an adequate calcium intake. The recommended daily intake is 1,000 to 1,500 milligrams. The latter is the equivalent to about 3 to 5 cups of milk each day. Men also need to ensure that thay have an adequate intake of calcium. The recommended amount for men ages 25 to 65 is 1,000 milligrams a day. Men over 65 need about 1,500 milligrams a day. Calcium supplements may be needed if a person's intake of calcium is inadequate.

Vitamin D helps your gastrointestinal tract absorb the calcium in the food you eat. Making sure that your body has enough vitamin D will help prevent osteoporosis. Your body manufactures vitamin D when your skin is exposed to sunlight. However, you probably will not have enough vitamin D in your body without additional dietary sources. Vitamin D is available in eggs, fortified foods such as dairy products, and fish. An adult needs about 400 international units of vitamin D each day. A glass of milk will provide about one fourth of your daily need.