Modern people eat more and more attention, a lot of calories has become the most valued food labels. This was originally a physics term, 1 calorie is equivalent to 1 g of pure water to enhance energy 1 need. Food science like to use "kilocalorie" this unit, it is easy to calculate. Among the three major nutrients, carbohydrates and proteins can produce about 4 kcal of energy per gram, fat is much greater energy density per gram of fat can produce about 9 kcal of energy, which is why most of the human body Cause excess energy is stored in the fat, the results can do so gave us enough to live comfortably modern brought endless trouble.
According to the current popular saying, the total energy a person eat every day foods contain minus that day consumed total energy is the person the net energy value of the day, this value and fat very close contact, if this value is positive , the extra energy is converted into fat, people will gain weight, contrary to burn fat to fill the gap, so a lot of people who intend to lose weight based on the total amount of calories consumed each day in the end to decide how much food to eat. The problem is that food calories algorithm or 19th century American chemist Wilbur? Art Watts (WilburAtwater) first proposed over the years has not been revised. Recently, many scholars have pointed out that this algorithm is out of date, the actual situation is far more on food packaging bags printed with numbers that much more complex. North Carolina State University nutritionist Robert? Dunn (RobDunn) in September this year on the issue of "Scientific American" (ScientificAmerican) magazine wrote a review article, which explains in detail the whole story.
Professor Dunn opinion, there are three major factors that determine the calories from different foods for different people have a completely different effect. First, the human digestive capacity is not the same. The most common reason is that the kind and content digestive enzymes are different, this is well understood. There are some less common causes can also lead to this result, such as the early 20th century, some people have studied different ethnic length of the colon, found that the average length of the large intestine Russia certain ethnic group to be vaccinated certain ethnic groups as much as 57 cm long ! The large intestine is a vital organ nutrient absorption, digestion illustrate the difference between the different groups of people there is a huge difference.
Human digestion and only their physical characteristics, but also on the type of intestinal microflora and a relationship. Human intestinal flora bacteria can be divided into the thickness door (Firmicutes) and Bacteroides door (Bacteroide-tes) these two types of fat human gut flora former is more, the reason may be that the wall thickness of the door of bacteria members are more adept at absorbing nutrients from food residue.
Secondly, the degree of digestible different foods are different. Before becoming human food is food of life, they are not born to human, it has its own logic of behavior. For example, many plant stems and leaves contain toxins, to prevent animals from eating them. Cultivation of human food and vegetables for many years, although the toxicity is very small, but the plant cell wall is still difficult to digest, you need outside help grinding, heat treatment, or some special action of the enzyme to break this barrier.
Another interesting case is that fruits and seeds. Fruit plants have evolved to attract animals to eat, he took the opportunity to spread the seed, and the fruit contains the seed but must be able to withstand the test of the digestive tract of animals, otherwise come to naught. That is why most of the high sugar content of fruit, easy to digest, the animals have a very attractive reason. The seeds, although rich in nutrients, but it is extremely difficult to digest. US Department of Agriculture scientist Janet? Ivanov Courtenay (JanetNovotny) and his colleagues last year in the "American Journal of Clinical Nutrition" (TheAmericanJournalofClinicalNutrition) published a paper, by analyzing the volunteers excrement, prove the value of calories almond actual net absorption of only about 170 kcal 129 kcal, nearly a quarter of the energy of the body can not absorb, eventually drained out.
Third, the digestion process itself consumes energy. The energy required for the body to digest different foods is also a great difference, which leads to huge differences in net energy value of different foods. For example, the monosaccharide is the most digestible food, almost without consuming any energy. Connected end to end by a single sugar molecule made of long chains of carbohydrates you need to consume some of the energy to break chemical bonds, which is why eat starchy calories values in the same situation much healthier than sugar directly causes. Fat is a very easy to digest food, protein is more difficult, under the same circumstances calories, protein digestion may need to consume more than five times the digestion of fat energy.
It is worth mentioning that not only the process of digestion takes energy, the body must also guard against the bacteria from food. If you experience more "dirty" food, the immune system will be mobilized to monitor the enemy, which also need to consume some of the energy. If the food in the "enemy" too much, the body will even activate an emergency system, through the "diarrhea" approach to undigested food from the body. Needless to say, the net energy value at that time you have to forget the other.
In short, the calorie value of the food is only an estimate, different food calories each other "fertility" effect varies greatly. To control weight, not only to reduce calorie intake, but also to minimize the intake of simple sugars and refined processed foods, eat more whole grains, lettuce and proteins.
(Author: Soil motorized)
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