Table below:
The calories contained in food are not equal to the calories absorbed.
Richard wrangham, an evolutionary biologist at Harvard University, studied the calories contained in food and how people digest and absorb them. I don't know if I don't learn. I was shocked when I studied it. He found that the heat meter was full of mistakes.
At present, the food calorimeter used to estimate calories was actually manufactured by Wilbur Olin atwater, an American agricultural chemist, at the end of 19 and the beginning of the 20th century. This is a very simple system. Protein is calculated at 4 calories per gram, fat at 9 calories per gram, carbohydrate at 4 calories per gram, and later generations added that cellulose is calculated at 2 calories per gram.
Together with the unit calories of these ingredients, the total calories of a food is the sum of the calories of its various ingredients. This is the origin of food calorimeter.
Wrangham found that the biggest problem of this system is the inaccurate heat estimation of cooked food. According to the past concept, cooked food is usually considered to contain less calories than raw food, because some food ingredients will be lost during cooking.
However, for meat, the process of cooking food makes the collagen in the meat gel, making the meat easier to chew and digest.
Judging from the energy consumption of human body to digest food, digesting cooked food consumes about 5% to 30% less energy than raw food, which does not count the reduction of gastric acid consumption. Because cooked food reduces the energy consumed by digesting food, wrangham thinks that cooked food should contain more calories than raw food when calculating calories, not the other way around.
Similar to meat, high temperature can denature protein in some vegetables, such as potatoes, thus making potatoes easier to be digested by the digestive tract and increasing the calories that people can absorb.
The way of food processing is very important for the absorption of heat. For example, starch contained in some barley and beans takes a long time to digest. But the same barley and beans are very easy to digest and absorb if they are processed into powder or instant things, such as porridge powder and bean powder.
According to scholars' rough estimation, for the same food, if the size of the food block doubles, the body energy required for digesting food will also double. This is why bread is easy to digest and beans are difficult to digest. The former is made of flour, while the latter remains unchanged.
Chewing with your mouth can make food pieces smaller and contact with digestive juice more fully, so you can absorb more calories.
In addition, the decomposition of intestinal bacteria also has an important impact on the digestion and absorption of food. The speed of food itself passing through the digestive tract is also fast and slow, some can get enough time to digest, while others are excreted before digestion. These factors need to be considered comprehensively when calculating calorie intake.
Extended data:
1. Aerobic exercise time is less than 30 minutes, and you can't lose weight.
In the first 30 minutes of exercise, you consume water and sugar in your body, and then you will start to consume fat after 30 minutes. Reducing water and sugar can only temporarily reduce weight, and only by consuming fat can we really achieve the goal of losing weight.
This is better than spending the cash in your wallet in the first 30 minutes and spending the money in the bank after 30 minutes. Short-term exercise lowers blood sugar in the body and causes hunger. If you eat and drink after exercise, you will gain weight.
2. Many people's exercise methods are chaotic and unscientific.
Exercise to lose weight requires a complete plan to get twice the result with half the effort.
3. Exercise intensity is also an influencing factor.
Exercise to lose weight is to promote energy consumption. At the same time of exercise, the energy consumption of high intensity is definitely much smaller than that of low intensity, so the weight loss effect is more obvious. Xiao Liu lacks exercise time and intensity every day.
References:
People's Network: What kind of exercise can lose weight best? The 60-minute Calorimeter for Various Sports tells you that,
Phoenix. Com: The heat meter deceived us.