Nutrients, Food & Cholesterol

Eating for Health

Food is the fuel that keeps the body alive, and the pleasures of the table are among the joys of life. Eating for health doesn't mean sacrificing these pleasures. The aim is to make eating enjoyable while curbing or eliminating habits that work against your long-term health and well-being.

The guidelines on this page will promote fitness and health by ensuring you get the nutrients you need without eating too much. They support good body growth and maintenance, decrease your risks of developing diet-related chronic diseases in middle age, and help ensure a good quality of life as you age.

These guidelines will help ensure you get sufficient vitamins and minerals, show you how to control sodium and cholesterol in your diet, and make you aware of possible food allergies.

The healthy eating principles outlined here apply to every family member and satisfy both taste and social customs. You'll find that a healthy diet consists of foods you enjoy, takes the drudgery out of cooking, and helps keep both waistlines and budgets under control.

Understanding Macronutrients

Food provides the mixture of nutrients that the body needs, not just for fitness and well-being, but for life itself. The three main classes of food are proteins, fats, and carbohydrates. They supply the body with energy and the basic building blocks needed for growth and maintenance. These are called macronutrients — foods you must eat in considerable quantities each day to stay healthy.

To maintain a healthy diet, you must choose your macronutrients wisely. This isn't always easy, as many traditional ideas about food continue to evolve as scientists learn more about nutrition and how our bodies utilize food.

For example, it was once widely accepted that meat is an ideal source of high-quality protein and that a perfect diet should contain substantial quantities of red meat. While red meat does contain plenty of high-quality protein, it's difficult to eat large amounts without also consuming harmful animal fat. Nutritionists have found there's no benefit in providing the body with more protein than it needs, and the protein quality in certain grains and legumes is excellent when used in the right combinations.

Proteins: The Building Blocks

The human body is made of proteins: the structural parts of body cells that prevent them from collapsing are protein-based, as are the working parts of all body cells. Every protein consists of building blocks called amino acids.

The human body needs about 22 amino acids to make all its proteins. It can manufacture 14 of these in its cells. The others, called the essential amino acids, must be obtained from food. Much of the body's chemical activity involves extracting amino acids from food sources and rearranging them into new proteins.

The Recommended Dietary Allowance (RDA) suggests 0.8 grams of protein per kilogram of body weight. For a 70kg person, this equals about 56 grams of protein daily.

Protein Sources

• Complete proteins (containing all essential amino acids): Meat, fish, poultry, eggs, dairy products
• Complementary proteins (combinations that provide all essential amino acids): Rice and beans, whole grain bread with nut butter, lentils with rice
• Plant-based proteins: Legumes, nuts, seeds, whole grains, some vegetables

Carbohydrates: Energy Providers

Carbohydrates are often underrated but are essential macronutrients. They provide the body with energy, help control the breakdown of protein, and protect the body against toxins.

Glucose is the chemical that fuels the body. All energy-producing chemical reactions in body cells are designed to use glucose, although they can use other fuels, including fats. Glucose is one of the carbohydrates known as monosaccharides — simple, single-molecule sugars.

Polysaccharides, of which starch is the most important, are composed of many monosaccharide molecules and are broken down by the body into simpler sugars. Commonly referred to as complex carbohydrates, they are found in fruits, vegetables, and grains.

Complex carbohydrates have high nutritional value, providing vitamins, minerals, proteins, and fiber in addition to energy-producing sugars. Because they take longer to digest than simple carbohydrates, they're more effective at preventing hunger.

Types of Carbohydrates

• Simple carbohydrates: Found in fruits, some vegetables, dairy, and refined sugars
• Complex carbohydrates: Found in whole grains, legumes, starchy vegetables
• Fiber: A type of carbohydrate the body cannot digest, important for digestive health

Fats: Essential But Moderated

Fats are an essential part of the diet, but too much of the wrong kind can harm your health. All dietary fats are composed of fatty acids — long molecules of carbon, hydrogen, and oxygen.

Fats produce more than twice as much energy as carbohydrates and proteins. They also carry vitamins A, D, E, and K. The body needs fats for growth and repair, and stored body fat insulates the body, helps maintain regular temperature, and cushions vital organs.

Saturation: The Key Factor

The most important feature of dietary fats is their degree of saturation, a term referring to their molecular structure. Unsaturated fats don't produce as much blood cholesterol as saturated fats. Since high blood cholesterol is associated with heart disease, experts recommend eating smaller quantities of saturated fats.

In the average diet, 35-40 percent of calories come from fat, about a third of which is saturated fat. The Heart Foundation suggests decreasing total fat consumption to 30 percent or less of total calorie intake and reducing saturated fats to about 10 percent.

All natural fats are a mixture of saturated and unsaturated fatty acids, but generally, animal fats are more highly saturated, while vegetable fats tend to be more unsaturated. There are exceptions: poultry and fish oils are high in unsaturated fatty acids, while coconut oil, a vegetable oil, is high in saturated fats.

Types of Fats

• Saturated fats: Found in animal products and some plant oils, generally solid at room temperature
• Monounsaturated fats: Found in olive oil, avocados, and certain nuts
• Polyunsaturated fats: Found in vegetable oils, fatty fish, nuts, and seeds
• Trans fats: Primarily found in processed foods, best avoided or limited

Understanding Cholesterol

Cholesterol is a complex waxy substance that's an essential component of cell walls. It's also used to make vitamin D, hormones, bile acids, and nerve tissues. Cholesterol is carried in the bloodstream by lipoproteins — proteins to which lipids (fats) are attached. Studies show that high blood cholesterol increases the risk of heart attack.

Cholesterol is present in food, and a considerable amount of blood cholesterol comes from the diet. However, the liver can produce enough cholesterol for vital body functions without dietary cholesterol. As a result, excess dietary cholesterol may be deposited in blood vessels, with the remainder eliminated.

Managing Cholesterol Levels

The best dietary way to reduce blood cholesterol is to lower your intake of all fats, particularly saturated fats, as well as high-cholesterol foods. Consuming a lot of saturated fat encourages the liver to produce large amounts of cholesterol.

The type of lipoprotein carrying cholesterol also influences coronary disease risk:

• LDL Cholesterol (Low-Density Lipoprotein): Most blood cholesterol is bound to LDL. The higher the LDL level, the higher the risk of coronary artery disease.
• HDL Cholesterol (High-Density Lipoprotein): This type appears to protect against heart attacks, so higher levels are better.

Most people consume about 450-500 milligrams of cholesterol daily, but health organizations recommend an intake of 300 milligrams per day or less. A simple way to reduce your intake is to moderate your consumption of eggs and organ meats, such as liver.

Annual checks of blood cholesterol levels are advised, particularly for men, from 20 years of age onward.

Tips for Healthy Eating

1. Eat a variety of foods to ensure you get all essential nutrients
2. Maintain a healthy weight by balancing food intake with physical activity
3. Choose a diet low in saturated fat and cholesterol
4. Choose a diet with plenty of vegetables, fruits, and whole grains
5. Use sugars and salt in moderation
6. If you drink alcohol, do so in moderation

Related Nutrition Resources

To learn more about nutrition and healthy eating, explore these related resources:

• Food Groups & Balanced Nutrition
• Healthy Eating Habits
• Fluids & Hydration
• Weight Loss Tips