Prerequisites: Definition and causes of obesity

Prerequisites

I. What defines obesity?

Obesity not only affects physical appearance but also leads to many diseases, thus impacting health. People generally believe obesity is simply exceeding the normal weight standard, but being slightly overweight doesn't necessarily mean obesity. So, how much above the standard weight is considered obese? There are many ways to calculate a person's ideal weight. The general standard is based on the average height and weight of people of normal height in my country. Two relatively simple formulas are as follows:

1. Height (cm) --- 1003 × 0.9 = Standard weight (T grams). Exceeding the standard weight by 10% is considered overweight, and exceeding it by 20% is considered obese.

2. Calculate using the Body Mass Index (BMI) formula: BMI = weight (kg) ÷ height (m) squared. A BMI between 18.5 and 24 is considered normal. A BMI exceeding 24 indicates obesity regardless of gender (Note: The World Health Organization, considering various global factors, defines obesity as greater than 27 for men and greater than 25 for women). For example, a person 1.7 meters tall, according to the formula: 1.7² × 24 = 70 (kg), meaning a weight exceeding 70 kg is considered obese.

II. Causes of Obesity

Obesity can be broadly categorized into two types: simple and secondary. Secondary obesity is mostly caused by neuroendocrine metabolic disorders, often secondary to conditions such as hypothalamic disease, pituitary disease, pancreatic disease, hyperadrenocorticism, and hypothyroidism or hypogonadism. It can usually be treated with medication or surgery to restore normal function. Simple obesity, on the other hand, does not present with obvious endocrine or metabolic disorders and is mostly due to overnutrition; some cases are related to genetic factors. This book focuses on individuals with simple obesity, who can achieve good weight loss results through dietary adjustments and exercise.

The material basis of obesity is the increased synthesis and accumulation of fat in the body. If daily calorie intake exceeds the energy required for expenditure, the remaining calories, besides being stored as liver glycogen and muscle glycogen, are almost entirely converted into fat and stored in fat stores throughout the body. Under normal circumstances, the body's calorie needs are related to age, sex, height, and nature of work. Because the normal neuroendocrine system has a precise regulatory function, a person's weight remains relatively stable and obesity does not occur. However, obesity may occur when the following factors are present.

More than 40% of individuals with simple obesity due to genetic factors have a family history of the condition. Often, the parents are obese, their siblings, and the individual themselves were obese from childhood, frequently accompanied by hyperlipidemia or hyperlipoproteinemia. Family members often have dietary habits such as consuming large amounts of oily food, a preference for sweets, and frequent, large-volume meals.

Neurological and psychological factors play a role. The hypothalamus in the brain contains a center that regulates appetite. When the hypothalamus is diseased, its function becomes relatively hyperactive, leading to gluttony and obesity. In addition, psychological factors often affect appetite, hence the saying "a relaxed mind leads to a plump body."

Metabolic factors: The metabolism of obese individuals differs significantly from that of normal-weight individuals. Under the same dietary conditions, their anabolism is more advanced, particularly with increased fat synthesis and decreased breakdown. Simultaneously, obese individuals have a lower stress response to changes in environmental temperature, resulting in reduced energy expenditure for heat production, making it easier to store energy as fat, thus leading to obesity. Traditional Chinese medicine believes that obese individuals often have a deficiency of Yang, meaning they produce less heat.

Hormones are important factors in regulating lipid metabolism. When the endocrine system is diseased (such as hypopituitarism, increased insulin secretion, hypothyroidism, hypogonadism, and adrenal insufficiency), hormone secretion imbalances can occur, leading to lipid metabolism disorders and obesity.

Dietary factors contribute to obesity. Obese individuals often have poor eating habits and preferences, such as frequently overeating, especially a fondness for greasy foods, sweets, or beer, frequent snacking, and a habit of consuming large amounts of food in a short period, leading to excessive intake of fat and sugar, thus easily causing obesity. Additionally, a habit of eating soft foods, late-night snacks, overly salty foods, and a reluctance to eat vegetables and other fiber-rich foods also contribute to weight gain. This is because soft foods are easily absorbed by the gastrointestinal tract, especially when eaten at night when insulin secretion is high, making absorption even easier.

Exercise is the best way to train the body and burn energy. If you lack exercise for a long time, even if you absorb nutrients normally, the excess calories will be converted into fat, leading to obesity.

Environmental factors: When society is affluent and food is plentiful, or when people eat large amounts of food to keep warm, obesity is more likely to occur. In addition, people who frequently cook and have a lot of contact with various foods are also more likely to become obese.