A healthy diet is based on good proportioning of food nutrients and on choosing the right type of nutrients:
Although an energy-providing nutrient, its main role is to ensure the material (amino acids) for tissue and muscle growth, maintenance and repair. Protein is made up of amino acids, it's these protein components that the body uses to build and repair muscles, skin, tissues and bones. They also help in hormone production.
Extra protein is converted to fat which the body stores and uses when carbohydrates and fats are not available. Protein is found in every food, it can be of two main types:
- animal — meat, eggs and dairy products, fish;
- vegetable — broccoli, lentils, soybeans, rice, nuts, potatoes, pasta, oatmeal.
For a healthy diet at least 10%-14% of calories should be protein-derived.
Is an energy-providing nutrient, helps nutrient absorption, nerve transmission, maintain cell membrane integrity. Fats are required to carry the “fat-soluble” vitamins A, D, E and K, which are also essential to good health. Extra fat results in weight gain, heart disease, cancer.
Depending on the atoms of hydrogen contained in the fat molecule, fats are: saturated (bad fats) and unsaturated (healthy fats).
Unsaturated fats are mono unsaturated and polyunsaturated.
Increase the level of LDL cholesterol, which is responsible for atherosclerosis and heart disease. Sources of saturated fats are: red meat, dairy products, tropical oils — coconut.
Vegetable oils are rich in unsaturated fats
Lower total cholesterol and LDL cholesterol and increase the HDL cholesterol. Nut, canola and olive oils are high in monounsaturated fats.
Also lower total cholesterol and LDL cholesterol. Seafood like salmon and fish oil, as well as corn, soy, safflower and sunflower oils are high in polyunsaturated fats. Fish is rich in Omega-3 fatty acids which are of particular interest to researchers because they help lower blood cholesterol. They are thought to have benefits related to some types of cancer. Like most nutrients, omega-3 fatty acids may have harmful effects if consumed in excess.
Trans Fatty Acids
Are human-made and are obtained when liquid vegetable oils are hydrogenated. This procedure turns unsaturated fatty acids into saturated fatty acids. The unsaturated fatty acids that do not become fully saturated may instead become trans fatty acids, which are thought to contribute to heart disease. Trans fatty acids lower levels of “good cholesterol” (HDL) and raise levels of “bad cholesterol” (LDL). Trans fatty acids are found in cookies, crackers, French fries (from some fast foods), packaged snacks such as microwaved popcorn as well as in vegetable shortening and hard stick margarine.
Generally, replacing saturated fats with unsaturated fats in a diet is considered to be beneficial in lowering cholesterol, but remember, even so total fat intake should still not exceed 30% of total calories. Thus:
- fat and trans-fat < 10% of calories,
- polyunsaturated fats < 10% of calories,
- monounsaturated fats = the reminder of total fat intake.
To understand the role of saturated fats vs unsaturated fats, one should know what cholesterol is and how it affects health.
Cholesterol is a fat-like substance called a lipid that is found in all body cells and that is produced in sufficient quantity by the liver. Extra cholesterol is not needed and it mainly enters our body when eating foods of animal origin. Cholesterol travels to cells through the bloodstream, by means of lipoproteins. Two of the most important lipoproteins are LDL and HDL.
LDL delivers cholesterol to the cells. High levels of LDL in the blood cause a fatty buildup (plaque) to form on artery walls resulting in atherosclerosis. HDL carry cholesterol from cells back to the liver, where it can be removed from the body.
High levels of HDL are thought to lower the risk of heart disease while low HDL levels increase this risk.
Is an energy-providing nutrient. Carbohydrates are converted to glucose — a type of sugar. The body uses this glucose for energy (this energy form is used by the brain). Extra glucose is converted into a sugar called glycogen which will be stored in the liver and muscles for future use. Finally, the leftover glucose is stored as fat.
Carbohydrates are :
- sugars — give the body a quick source of energy, because they can be used right away. Added sugars found in candy and soft drinks add more calories than nutrients, that is why it is advisable for sugars to be taken from fresh fruit, as they add vitamins and minerals to the diet. Found in refined or brown sugars, syrups, and honey.
The body must decompose them to use the sugar they contain.
- starches lower the risk of coronary artery disease. Found in breads, pasta, cereals, peas, potatoes, rice.
- fiber reduce cholesterol levels and help protect against heart disease, cancer, stomach and bowel problems. Fiber can be soluble (oatmeal, dried beans, peas, and many fruits, including apples, strawberries, and citrus fruits) and insoluble (found in cereals, whole-grain breads, rice, and many vegetables).
Around 50% of total calories should be derived from carbohydrates, mostly complex ones.
Considering the same amount of carbohydrate, foods with a lower GI raise blood glucose less than those with high GI values. High level GI foods will result in marked fluctuations in blood sugar levels, which are not healthy because of the stress they place on the body determining the pancreas to secrete insulin to drop blood-sugar levels. Thus insulin-level increases which will eventually lead to a depression of the immune system.
The GI of foods has been established as most important information about the food we eat, even more important than information on complex carbohydrates and sugars, which commonly appear on food labels. Instead, labels should contain info on the total carbohydrate content of the food and its glycemic index value.
Adjust chemical processes including those that convert food into energy and into tissue and regulate the body's metabolism, which controls the amount of energy used when walking, sleeping, thinking etc.
There are thirteen vitamins required for good health and they are water-soluble (B-complex vitamins and vitamin C) and fat-soluble (vitamins A, D, E and K).
Every process necessary for life in our body depends on minerals. The major minerals are calcium, phosphorus, magnesium, sodium, potassium and chloride, which are present in our body in the largest amounts.
All chemical processes occurring in the body require water, as well as almost all bodily functions (digestion, circulation, absorption, excretion, etc.). Adult body weight is 60% water, and child body contains even more water. Water is in every body cell.
The daily need of water with adults is six to eight cups. Water is contained in fruit juice, milk, soups, coffee, tea or soft drinks but also in solid food in small amounts.