Weight Loss:چطور بهداشتی بخوريم
Nutrition 101: How to Eat Healthy
Most health experts recommend eating a balanced, healthy diet to maintain or lose weight. But what is a healthy diet?
The basic components of a healthy diet include the right amount of:
- Protein (found in fish, meat, poultry, dairy products, eggs and beans)
- Fat (found in animal and dairy products, nuts, and oils)
- Carbohydrates (found in fruits, vegetables, pasta, rice, grains, beans and other legumes, and sweets)
- Vitamins (such as vitamins A, B, C, D, E, and K)
- Minerals (such as calcium, potassium, and iron)
What Are Calories?
Of these six nutrients, only carbohydrates, proteins, and fats provide calories. A calorie is a measurement, just like a teaspoon or an inch. Calories are the amount of energy released when your body breaks down food. The more calories a food has, the more energy it can provide to your body. When you eat more calories than you need, your body stores the extra calories as fat. Even low-carb and fat-free foods can have a lot of calories that can be stored as fat.
What Are Proteins?
Proteins are nutrients that are essential to the building, maintenance, and repair of body tissue such as the skin, the internal organs and muscle. They are also the major components of our immune system and hormones.
Proteins are made up of substances called amino acids -- 22 are considered vital for health. Of these, the adult body can make 14; the other eight (called essential amino acids) can only be obtained from what we eat.
Proteins are found in all types of food, but only fish, meat, eggs, cheese, and other foods from animal sources contain complete proteins, meaning they provide the eight essential amino acids.
Your daily diet must contain enough protein to replenish these amino acids. Thus, if you are vegetarian and do not eat food from animal sources, you need to eat a variety of plant proteins in combination to ensure that you get enough of the essential amino acids.
The new dietary reference values for protein for adults are 0.8 grams per kilogram of body weight. This translates to about 0.36 grams of protein per pound.
However, over the course of a day, the average American diet includes almost double the protein needed to help maintain a healthy body. Using the chart below, you can easily calculate how much protein your body needs.
Suggested Daily Grams of Protein
Is Any Fat Healthy?
A certain amount of fat in the diet is good and necessary to be healthy. Adults should get 20%-35% of their calories from fat. However, nutrition experts agree that most Americans should eat less fat than they currently do. Research shows that excessive intake of fat -- especially trans fat and saturated fat -- and cholesterol increases the risk of heart disease. Eating too much fat can cause excess body weight, since a gram of fat has about twice as many calories per gram as carbohydrates (see below) and proteins. (There are 9 calories per gram of fat compared with 4 calories for protein and carbohydrates.)
Fat is made up of compounds called fatty acids or lipids. Depending on their chemical structure, these fatty acids are called monounsaturated, polyunsaturated, saturated, or trans fats. Trans fats and saturated fats are the unhealthiest fats to eat. Trans fats are formed when manufacturers turn liquid oils into solid fats, such as with shortening and hard margarine. Trans fats can also be found in many foods, including crackers (even healthy-sounding ones), cereals, baked goods, snack foods, salad dressings, fried foods, and many other processed foods.
Problems with too much dietary fat can aslo come when 10% or more of your daily calories come from saturated fats such as those found in meats, high-fat dairy products, and butter and foods cooked or made with hydrogenated fats. And consuming trans fats in any amount is also not recommended. These practices may lead to high blood cholesterol levels and heart disease.
What Are Carbohydrates?
Carbohydrates provide fuel for the body in the form of glucose. Glucose is a sugar that is the primary source of energy for all of the body's cells. Adults should get about 45%-65% of their calories from carbohydrates.
Carbohydrate sources include many foods that are nutrient-rich such as whole grains, fruits, vegetables, and legumes, as well as foods such as candy, pastries, cookies, and flavored beverages (soft drinks and fruit drinks), which provide insignificant amounts of vitamins, minerals and other essential nutrients.
What Are Vitamins?
Vitamins help with chemical reactions in the body. In general, vitamins must come from the diet; the body doesn't make them.
There are 13 vitamins essential to the body. They are divided into two categories: water-soluble (vitamin C and all the B vitamins) and fat-soluble (vitamins A, D, E and K). The fat-soluble vitamins are more easily stored by the body. Thus, you do not need large amounts of these vitamins since excess amounts can be toxic and cause a variety of problems.
Because the water-soluble vitamins aren't stored for long in the body, we must consume them daily. And, although taking large doses of these vitamins isn't necessarily dangerous, it may be wasteful as the body eliminates the excess water-soluble vitamins in the urine.
What Are Minerals?
Minerals, like vitamins, must come from the diet; the body doesn't make them. Many minerals are vital to the proper function of the body and must be taken in relatively large amounts (such as calcium, potassium and iron.) Others, like trace minerals (zinc, selenium and copper), are only needed in small amounts to maintain good health.
How Does Water Promote Health?
Although it has no food value, water is essential to our survival. It keeps the body adequately hydrated. Water is the most plentiful substance in the body, accounting for 55%-65% of body weight, but because the body can't store water, we must constantly replenish it.
What Makes Up a Healthy Diet?
A healthy diet should consist of:
- 45% to 65% carbohydrates.
- 10% to 35% protein.
- 20% to 35% fat, with no more than 10% saturated fat and very little (or no) trans fat.
The Food Pyramid published by the USDA makes it easy to envision just how much of each food type you should eat.
Each section of the pyramid represents a food group; the size of the group corresponds to the number of recommended servings. The base of the pyramid represents the grain group. These are carbohydrate-rich foods like bread, cereal, rice and pasta. You should eat six to 11 servings per day of these foods. The next tier of the pyramid includes vegetables and fruit. You should eat three to five servings per day of vegetables and two to four servings per day of fruit. These are good sources of vitamins, minerals and fiber. The next level is protein, like dairy products, meat, poultry, fish, dry beans, eggs and nuts. You should eat two to three servings per day of foods from the milk group and two to three servings per day of foods from the meat, egg, bean and nut group. The top level of the pyramid is fats, oils and sweets; these should be used sparingly.
The pyramid calls for eating a variety of foods to get all of the nutrients you need, and, at the same time, the right amount of calories to maintain a healthy weight. If you're watching your weight, eat the minimum number of recommended servings. If you need to gain weight, eat the maximum number of servings. And, keep in mind as to what constitutes a serving. Most serving sizes are smaller than you think. Be sure to read the food labels carefully to determine the accurate portion size.
Also, try to choose nonfat and lean foods as often as possible. For example, choose nonfat or 1% milk instead of 2% or whole milk; lean meat instead of fatty meat; and breads and cereals that are not processed with a lot of fat.
But you don't have to completely avoid all foods that have fat, cholesterol, or sodium. It's your average over a few days, not in a single food or even a single meal that's important. If you eat a high-fat food or meal, balance your intake by choosing low-fat foods the rest of the day or the next day. Read the food labels on everything you eat to help you "budget" your fat, cholesterol, and sodium over several days