Every diet comes with its own rules and promises: "Do this and you'll achieve that". Diet promises are often based on half truths, unproven information and irrelevant research studies. In the worst case they are based on your search for the "the ultimate diet". That's the magic formula that can make you slimmer, younger, healthier, probably in this particular order. Dietary programs and scores of "magic products" which sounded so exciting at the time have proved to be nothing more than marketing strategies.
There's nothing wrong with following a weight loss diet. But before you start, you should do at least two things:
- Find out more about diet nutrition facts and human body functions
- Talk to your doctor to see if the diet is fit for your metabolism and state of health
The six major nutrients
Why carbohydrates are important
Carbohydrates are the favourite, cheapest source of energy for the human body. Simple carbohydrates are easy to digest and quickly absorbed. They can be found in sugar and sweets, honey, fruits and fruit juices. The simplest carb is glucose.
Complex carbohydrates can be found naturally in starches and fiber. Starches are absorbed slowly, as they have to be broken into simple carbohydrates first. They can be found in plants, vegetables, grains. Fiber does not supply much energy to the body and usually it is not digested. It is however helpful in regulating blood sugar and in eliminating waste through the intestines. A diet low in fiber can lead to constipation and even colon cancer.When we eat carbs, the simple ones pass directly into our blood system. Insulin secretion is stimulated. Insulin is a hormone that helps glucose reach tissues and supply energy. If there is any glucose left, insulin stores it in muscles and liver as glycogen (one glucose molecule with two molecules of water). And if, after that, there is still some glucose left, insulin stores it as fat in the fat cells. The complex carbs follow the same process after being transformed into simple carbs. Brain activity is sustained only through glucose feeding.
When we don't eat carbs, this stmulates the secretion of glucagon. Glucagon is a hormone that carries out the opposite function of insulin. First, it helps to release glucose from glycogen storage. Of course, water molecules are also released and eliminated. If we continue not to eat carbohydrates, glucagon releases fat from the fat tissues and helps to process it back to simple carbohydrates, to supply our energy needs.
The problem with carbs is that they usually come in foods with a high glycemic index. This index measures how quickly the food we eat is processed into glucose and enters the bloodstream. Overconsumption of high glycemic foods provokes rapid increase in blood sugar, and overproduction of insulin (hyperinsulemia). Insulin tries to "work" as quickly as possible, absorbing glucose from the blood. Sugar blood level decreases rapidly. These wide fluctuations of blood sugar level have been associated with moodiness, rapid fat storage, increase of LDL cholesterol, decrease of HDL cholesterol, high blood pressure and several other problems. Together, they create "Syndrome X".
Why proteins are important
If glucose is "fuel" for the body, protein is "building material". It builds blood, muscles, organs, skin, hair, nails. Protein is formed of 22 amino acids, eight of which the body is not able to produce, and must come from our diet. These are called essential amino acids. All amino acids must be present for the production of protein, tissue building, creating the hormones, enzymes and other functions. The excess protein we consume is converted to fat. Protein is converted to energy only when glucose and fat storage are complete.
Why fats are important
Fats are a secondary, very concentrated, source of energy that our body uses. We can either eat fat, or produce it from excess glucose. The human body stores as fat all the energy it does not need for the burning processes. In fact, our body is a very "low consumption machine". It uses as little as possible energy for burning, and stores more for rainy days. Fat dissolves and carries some of the vitamins that are not water-soluble. Like proteins, fats include some essential fatty acids that the body cannot produce and thus must be provided by food. Fatty acids can be saturated, monounsaturated and polyunsaturated.
Fats or lipids are stored in fat cells. We are born with some of these fat cells. The rest develop at puberty. After this period, fat cells do not multiply anymore. They can enlarge and store more lipids. The fat we ingest is carried into the fat cells through a complex process. This process depends on the insulin level in the blood. Insulin activates enzymes called lipoprotein lipases which break down the fats into fatty acids.)
Eating too many saturated fats is associated with high LDL cholesterol levels. LDL cholesterol is also known as "bad cholesterol" and causes blood-vessel diseases. Mono- and polyunsaturated fats provide both LDL and HDL cholesterol.
Cholesterol is a fat-like substance that belongs to the steroids group. Cholesterol insulates cells and protects them from temperature variations, to help create sex hormones, bile salts, (to help digestion), and produce vitamin D in skin tissue when exposed to the sun.
Our body is able to produce the cholesterol it needs to function properly. But we also ingest cholesterol. The discussion about "good" and "bad" doesn't refer to cholesterol itself but to the molecules that carry it. Apoproteins are compounds that can dissolve and carry cholesterol and lipids. Apoproteins combined with lipids form lipoproteins. "Bad cholesterol" is in fact Low Density Lipoprotein (LDL) and "good cholesterol" is High Density Lipoprotein (HDL). HDL is able to solve and carry lipids and cholesterol, while LDL is less able to do that. When we go to the doctor and ask for a cholesterol level test, he or she measures total cholesterol, HDL and LDL levels in the bloodstream. Two situations are considered "high heart attack risk":
- High total cholesterol levels in the blood, even if the HDL/LDL ratio is good;
- High LDL levels, even though total cholesterol levels are low.
Carbohydrates, fats and proteins are nutrients with energy value. The energy value measures in calories.
Why vitamins are important
Vitamins are nutrients that our body cannot produce. They have no energy value, although they help to convert fat and carbohydrates into energy. They contribute to many metabolic functions and help to develop body structures. There are two classes of vitamins:
- fat soluble:
- vitamin A (cortisol) --- lack of it leads to poor eyesight, night blindness, dry skin, and inappropriate bone development. An excess of vitamin A can be very toxic to human body. It is stored in the liver;
- vitamin D (cholecalciferol) --- precursors of vitamin D are assimilated from foods like milk and stored in the skin. In contact with ultraviolet light, these D-precursors turn into D3 vitamin, "or natural vitamin D". This helps calcium and magnesium assimilation. Fish liver oil and butter are good sources of vitamin D;
- alpha-tocopherol (Vitamin E) --- fulfils the functions of an enzyme. It collects free radicals that can damage membranes and cell components. Vegetable oils are a source of vitamin E.
- Vitamin K (menadione) --- helps the bood cloting process. It can be found in green vegetables, and, in small amounts, in eggs and dairy products;
- water soluble:
- vitamin C (ascorbic acid) --- is an antioxidant. It collects free radicals and is popular as an antiviral agent, although this last function is controversial. It is commonly found in fresh vegetables and fruit (peppers, tomatoes, citrus fruits). Severe lack of vitamin C can lead to scurvy;
- B complex
- B1 (Thiamine) --- maintains normal functioning of the nervous system, muscles and heart. It helps in the growing process and can be found in flour, beans, pork, salmon, soybeans. Lack of thiamine leads to beri-beri
- B2 (Riboflavin) --- also involved in the growing process, helps in the formation of red blood cells, steroids and glicogen. It also contributes to breaking down fat. Almonds, yeast, cheese, eggs, chicken and other kinds of meat are sources of riboflavin. People who lack vitamin B2 develop inflamations, insomnia, dizziness and problems with memory;
- B3 (Niacin) --- is found in legumes and whole grains. Lack of niacin leads to a severe disease called pellagra;
- B6 (Pyridoxine) --- helps with brain functions and blood cell formation. It is also involved in the metabolism of macronutrients (protein, carbohydrate and fat. Common sources of vitamin B6 are bananas, carrots, nuts, rice, fish, soybeans.
- B12 (Cyanocobalamin) --- can be found in eggs and dairy products and helps normal growth.
- B9 (Folic acid) --- another vitamin that helps growing processes, especially fetus development during pregnancy. Brewer's yeast is a rich source.
- B5 (Pantothenic acid);
- Biotin acts as a carbon dioxide-carrier. It produces antibodies and digestive enzymes.
Why minerals are important
Minerals are substances that can not be produced by the human body. Several of them are very important to its functioning. That is why we need to ingest them. They are important for the metabolism, hormone production, bone development and other biological functions.
Why water is important
Water represents most of our body composition ( 70% to 80%). Water is a favorable medium for cell metabolic reactions and helps to maintain a stable body temperature.