Is fat all harmful to no benefit?

Speaking of “fat”, many people naturally think of a body that gradually gains weight due to ingestion of fat, so they are afraid of it. Actually, you have misunderstood it all the time. Although excessive fat intake can cause obesity, the lack of fat in the body can also cause a series of health problems. For women, lack of it will also affect the appearance. How does fat maintain human health? How to eat the right fat scientifically? The reporter interviewed Cheng Yiyong, former chairman of the Chinese Nutrition Society, and Fang Yu, director of the Nutrition Department of Peking University Cancer Hospital.

How important is fat to the human body?
In terms of chemical composition, fat is a “triacylglyceride” composed of glycerol and fatty acids. Its shadow can be seen everywhere in life: the fat on the chopping board, the grease in the dishes, and the “swimming ring” on the belly…

Fat is mainly distributed in subcutaneous connective tissue, peritoneal omentum and mesenteric, etc., often in the form of bulk fat. Body fat percentage refers to the proportion of body fat weight in the body’s total body weight, also known as body fat percentage, which reflects the amount of body fat in the body. The normal range of body fat rate for adults is 20% to 25% for women and 15% to 18% for men. Infants and young children are slightly higher.

The types of foods we eat every day can be divided into three categories: carbohydrates, fats and proteins. If you eat too much energy-producing food that cannot be consumed, the excess energy will be stored in the form of glycogen and fat to provide energy during fasting and hunger. The storage of glycogen is limited, but fat can be stored “unlimited”. When the intake of energy exceeds the body’s needs, fat will continue to be produced, and finally it will become excess “fat”.

Obesity is a risk factor for many diseases, and some people even claim that “obesity is the source of all diseases”, causing people to avoid fat. In fact, fat is an important component of body cells, especially the brain, liver, kidneys and other organs. Among the eight essential nutrients for the brain, fat ranks first, and is mainly used to generate new cell membranes and maintain existing cell membranes; infants’ brain and intellectual development especially need fat; fats can also prevent brain degeneration caused by aging Variety.

Fat also plays an important role in the process of life activities. If it is lacking, it will cause a series of health problems.

1. Energize the body

When the body needs energy, fat will be broken down to release glycerol and fatty acids into the blood circulation, releasing energy to meet the body’s needs.

2. Provide essential fatty acids

Essential fatty acids cannot be synthesized by the human body and must be obtained from food, including linoleic acid and linolenic acid, which are polyunsaturated fatty acids necessary for the body’s growth and development and normal skin metabolism.

3. Support the internal organs

The adipose tissue around the organ can support and cushion the organ and protect the organ from external force damage.

4. Help absorb nutrients

Fat contains fat-soluble vitamins such as vitamins A, D, E, and K, which can provide nutrition for the body. At the same time, fat can also promote the absorption of this part of the vitamin.

5. “Protection” protein

Adequate fat can protect the body’s protein from being consumed as an energy source, so that protein can effectively play its important physiological role.

6. Maintain body temperature

Fat is not easy to dissipate heat, so it can maintain a constant body temperature and resist the cold.

7. Participate in endocrine function

Cytokines secreted by fat, such as leptin, interleukin, tumor necrosis factor, etc., participate in various physiological processes of the body such as metabolism, immunity, growth and development.

8. Promote appetite and increase satiety

When food fat enters the duodenum from the stomach, it can stimulate the production of enterostatin, which inhibits intestinal peristalsis, resulting in a relatively slow speed of food entering the duodenum from the stomach, prolonging the residence time in the stomach, and increasing satiety.

For women, if you lack fat, it may make you “ugly” and also cause menstrual disorders:

1. Poor skin condition and hair loss

Diet to lose weight leads to malnutrition, which can cause dryness and dullness of the skin on the face, and the skin on the face and body lacks the support of fat, and will become loose; the quality of hair will also be affected, such as thinness and dryness, and even hair loss. .

2. Affect menstruation and fertility

When the body fat content is below a certain level, it will cause the supply of estrogen and progesterone to fail to keep up, leading to menstrual disorders. Excessive weight loss may also cause women’s ovarian function to decline, menstrual flow decreases, menstruation is early or delayed, or even amenorrhea, and serious problems such as premature ovarian failure.

Learn to balance body fat correctly
So, how can we seek advantages and avoid disadvantages, and control the negative effects of fat while exerting the health benefits of fat?

Experts suggest that 20% to 30% of total dietary energy is provided by fat. However, animal foods are high in saturated fatty acids, and their calories should not exceed 10% of the total calories. For the current diet of most people in our country, it needs to be slightly lighter and less oily, cooking oil should not be too much, eating nuts should be controlled in quantity, and fish and meat should not be fried frequently.

Specifically, the following should be done:

1. People who are overweight, control total calories

Internationally, it is recommended to use the body mass index (BMI) to measure whether a person’s weight is healthy. The algorithm is: weight (kg) divided by the square of height (m). The normal range is 18.5-23.9, overweight is 24-27, obesity is 28-32, and higher than 32 is very obese.

People who are overweight should keep their mouths shut, open their legs, and control total calories under the premise of a balanced diet and comprehensive nutrition. When eating meat, choose low-fat and high-protein shrimp, skinless poultry, etc., and pay attention to controlling the intake of fatty foods such as fatty meat and edible oil.

2. Grasp the total amount and eat fat differently

Food fat is divided into saturated fat and unsaturated fat. Unsaturated fat is divided into monounsaturated fatty acid and polyunsaturated fatty acid.

Eat less saturated fatty acids. Lard, butter, tallow, coconut oil, and palm oil have a relatively high percentage of saturated fat. Although they can make foods crispy, they contain more cholesterol. Excessive consumption is not conducive to cardiovascular and cerebrovascular health.

Monounsaturated fatty acids can be eaten in moderation. The main components of olive oil and tea seed oil are monounsaturated fatty acids. Peanut oil, sesame oil, rice bran oil, and canola oil also contain some. Appropriate intake of these fats will help lower blood lipids, prevent blood clotting, and delay atherosclerosis. Plaque formation.

Eat polyunsaturated fatty acids deliberately. Linoleic acid, EPA, and DHA are typical representatives of polyunsaturated fatty acids and need to be supplemented deliberately. Linoleic acid can help lower blood cholesterol and prevent atherosclerosis. Because the body cannot synthesize or synthesize very little, it must be obtained from soybean oil, corn oil, sunflower oil, wheat germ oil and other foods. EPA and DHA are also very important for physiological functions. Generally, the content of food is relatively small, so they need to be supplemented by eating more and more fatty fish.

It is worth reminding that even if some edible oils have health benefits, it is still necessary to control the total intake of 25 to 30 grams per day.

3. Keep exercising, “anaerobic + aerobic”

Some people are not overweight, and their body mass index is within the normal range, but the partial body fat rate is very high, and even fatty liver and other problems need to be paid attention to. Exercise is one of the good ways to maintain the balance of fat in the body. For people with abundant body fat reserves, a combination of anaerobic exercise and aerobic exercise is the best way. You can try anaerobic first and then aerobic. First use anaerobic exercise to consume the excess sugar in the body, and then use aerobic exercise to reduce the excess body fat. Do anaerobic exercise for 15-20 minutes each time, and aerobic exercise for 30-40 minutes. Do at least 4 to 5 times a week. It is best to exercise every day.