Understanding Obesity: Definition, Common Causes, and Stages of Weight Gain in Life

**Common Knowledge about Obesity**

**★What is obesity? What are the common causes?**

Generally, exceeding the standard weight by 10% is considered overweight, while exceeding it by 20% is considered obese. Obesity is further classified into mild obesity (overweight by 20%), moderate obesity (overweight by 30%), and severe obesity (overweight by 50%), depending on the degree of excess. In recent years, numerous newspapers and magazines have published discussions on the causes and treatments of obesity, and many treatment methods and drugs have emerged. Regardless of their effectiveness, the analysis shows that the factors causing obesity are diverse, mainly including the following:

**(1) Heredity**

Nowadays, it is common to see many people in some families who are obese. Some scholars have investigated the family history of obese patients and found that 34.3% of them have a family history of obesity.

**(2) Changes in metabolism and endocrine function**

Obesity is caused by metabolic abnormalities, mainly in carbohydrate metabolism, sugar metabolism, and fat metabolism; changes in endocrine function are mainly due to abnormalities in the metabolism of insulin, adrenocortical hormones, and growth hormone.

**(3) Lifestyle and Diet**

People's eating habits and the quality of their diet also have a certain impact on the occurrence of obesity. Inappropriate pursuit of high-sugar, high-fat, and high-protein diets, especially excessive intake of animal offal and animal fat, as well as snacks and frequent drinking of large amounts of beer, often easily leads to obesity.

**(4) Psychological factors**

It manifests as an intense appetite for a certain food, and people reflexively stimulate their appetite through visual, olfactory, and artificial eating contests, resulting in a doubled food intake. It is also a form of hyperphagia in some mental patients.

**(5) Physiological factors**

Men in middle age and women after menopause often experience a decline in various physiological functions and reduced physical activity, but if their diet is not reduced accordingly, they are prone to accumulating body fat and gaining weight. Some women who have good nutrition during pregnancy and breastfeeding, but fail to participate in sufficient physical activity or exercise after childbirth, may also become obese.

**Is obesity harmful to the human body?**

In modern society, with the continuous improvement of living standards and the gradual decrease in physical exertion, the accumulation of fat in the human body has increased significantly. The number of obese people in society is growing rapidly, posing a serious threat to human health and becoming a thorny issue for medical professionals.

Globally, it is estimated that approximately 50 million men and 60 million women are obese, with the incidence rate even higher due to geographical and lifestyle factors. According to a survey by the World Weight Watch Society, over 50% of Germany's population of 61.4 million is overweight, 44% in Mexico, and over 40% in Switzerland and Australia. Obesity is also quite common in my country.

Extensive surveys on obesity have been conducted across all provinces and cities in China. The data revealed that the dangers of obesity are alarming, with an increasing incidence rate among children, which seriously affects the physical health of future generations.

**★What are the different types of obesity?**

Obesity can be classified in several ways. A common method is to divide it into simple obesity, secondary obesity, and drug-induced obesity.

(1) **Simple obesity**

Simple obesity is the most common type of obesity, accounting for approximately 95% of obese individuals. These patients have relatively evenly distributed body fat, no endocrine disorders, and no metabolic diseases; their families often have a history of obesity. This type of obesity, primarily caused by genetic factors and overnutrition, is called simple obesity.

**(2) Secondary obesity**

Secondary obesity is caused by endocrine and metabolic diseases. It is a type of pathological obesity, accounting for approximately 2%-5% of obesity cases. Common types include: ① Hyperadrenocortical obesity ② Pituitary obesity ③ Pancreatic obesity ④ Hypothalamic obesity ⑤ Hypogonadism obesity ⑥ Hypothyroidism obesity. Treatment primarily focuses on addressing the underlying disease; exercise and dietary control methods are not recommended.

**(3) Drug-induced obesity**

Some medications, while effectively treating certain diseases, can also cause weight gain as a side effect. For example, corticosteroids (such as hydrocortisone) used to treat allergies, rheumatism, rheumatoid arthritis, and asthma can also cause weight gain; phenothiazines used to treat mental illness can also cause sexual dysfunction and obesity. This type of obesity accounts for approximately 2% of all obesity cases. Generally, the obesity will improve on its own once these medications are discontinued. Unfortunately, some patients develop "refractory obesity" as a result.

**★When are people most prone to obesity?**

Throughout a person's long life, weight gain is not common at every stage. It is more common during certain periods when intake exceeds expenditure or when anabolism exceeds catabolism.

(1) **Infancy and early childhood**

For a long time, people have believed that infant obesity is a sign of health. Therefore, parents generally hope their babies are as chubby as possible. This is especially true for parents of only children, who often have better economic conditions and are very concerned about their baby's nutrition. As a result, in addition to breastfeeding, infants are often formula-fed, and solid foods (mostly rice, noodles, sugar, and other high-energy carbohydrates) are introduced too early (1-2 months after birth). In the first three months, infants cannot yet move around, and they sleep after being fed, resulting in low energy expenditure. Therefore, overfeeding leads to intake exceeding expenditure, promoting infant obesity. With social development and improved living standards, children's cravings are often met. This fosters picky eating habits in children. Over time, this leads to energy storage in the body, resulting in childhood obesity.

**(2) Puberty**

During puberty, the ovaries in women and the testes in men become highly active, leading to a surge in sex hormone secretion. Estrogen in women affects metabolism, causing a significant increase in subcutaneous fat in teenage girls. Simultaneously, during this period, children often have heavy academic burdens and less time for physical activity and exercise. Therefore, the combination of increased intake and decreased expenditure easily leads to weight gain.

**(3) After marriage**

Young married couples often develop regular eating habits due to cooking and eating together. At the same time, their social activities decrease significantly. Especially now that living conditions are relatively good, with complete household appliances and less housework, coupled with a happy mood and delicious food, it doesn't take long for them to gain weight.

**(4) Pregnancy**

After conception, as the fetus grows, weight gain during pregnancy is primarily due to excessive energy intake and reduced physical activity. The increasing size of the fetus, placenta, and reproductive organs during pregnancy leads to an average weight gain of 10 kg. In the first three months of pregnancy, weight gain ranges from 0.25 to 2.7 kg, with an average of 0.9 kg. In the fourth, fifth, and sixth months, the range is 3.6 to 6.6 kg, with an average of 4.0 kg. In the seventh, eighth, and ninth months (without preeclampsia), the average weight gain is 4-5 kg. Generally, it is considered that weight gain during pregnancy should not exceed 12.5 kg. Significant weight gain indicates excessive fat deposition. Many families now try to increase the nutrition of pregnant women in hopes of giving birth to a healthy baby. However, during this period, physical activity is greatly reduced, energy expenditure decreases significantly, and fat storage is promoted. Therefore, obesity can occur quickly.

**(5) Middle and old age**

As people reach middle age, their physical activity decreases significantly, but the secretion of sex hormones remains at a relatively high level. This directly affects the metabolism of proteins and fats in the body, providing a favorable opportunity for weight gain. Surveys show that dividing mental workers over 45 years old into seven age groups-45-49, 50-54, and 55-59-reveals that the number of people with normal body types gradually decreases with age. Obese individuals account for approximately 6.15% in the 45-49 age group, gradually increasing the percentage thereafter. It peaks at 26.85% in the 55-59 age group, then gradually declines with age, reaching its lowest point at only 6.06% after age 75. Therefore, 55-59 years old is one of the age groups most prone to obesity.

As people enter middle and old age, they have achieved success in their work, no longer need to be too stressed about their studies, and their children have grown up. Therefore, they are generally happy, financially secure, and have a stable life. Consequently, older adults often focus on improving the quality of their diet. At the same time, hormonal changes after menopause disrupt fat metabolism, leading to increased fat storage and obesity.