How to scientifically diagnose obesity? Analysis of common weight loss misconceptions and correct methods.

How to determine if you are overweight?

Whether someone is overweight depends on their height, weight, and circumference, as well as their age and general physical condition. Most cases of obesity during puberty and after childbirth in women can be corrected through increased exercise. However, weight gain outside of these periods is more difficult to reverse.

The following data can be used as a reference to determine whether someone is overweight:

(1) Standard weight formula
Women: [Height (cm) - 100] × 0.9 = Weight (kg)
Men: [Height (cm) - 100] × 1 = Weight (kg)

(2) Children: Age × 2 + 8 = Weight (kg)
Standard measurements for women
Standard bust = Height × 1/2 (cm)
Standard waist = Height × 1/2 - 20 (cm)
Standard hip = Height × 1/2 + 4 (cm)
Standard thigh = Height × 1/2 - 30 (cm)
Standard calf = Height × 1/2 - 50 (cm)

The causes of weight gain are multifaceted, not just the increase in adipose tissue. For example, the muscle development of athletes (especially bodybuilders) or patients with severe edema may cause their weight to exceed the normal range, but this does not necessarily mean they are obese. Conversely, a weight that is not overweight does not necessarily mean one is not obese. Obesity is caused by a comfortable lifestyle, lack of exercise, and insufficient energy expenditure, leading to fat accumulation and the replacement of muscle tissue with adipose and connective tissue, resulting in excessive body fat. Another type is localized fat accumulation, such as a "general's belly," which, even if the weight is less than 20% above the standard weight, can still be called "abdominal obesity."

Do weight-loss drugs really reduce fat?

Currently, weight-loss drugs on the market mainly fall into three categories based on their mechanism of action: First, appetite suppressants, such as dextromethorphan, whose main mechanism of action is to stimulate the satiety center in the brain, causing a decrease in appetite and thus reducing food intake. Second, dehydrating agents, such as senna leaves, whose main mechanism of action is to stimulate the large intestine mucosa, promote peristalsis, and reduce the reabsorption of water in the large intestine, thereby achieving weight loss. Furthermore, there are stimulants. Their main mechanism of action is to stimulate the central nervous system, putting the person in a state of sustained excitement, causing loss of appetite, insomnia, hyperactivity, and a feeling of heat throughout the body. This reduces calorie intake and increases calorie expenditure, thereby achieving the goal of weight loss.

From the above, it is clear that weight-loss drugs themselves do not reduce fat; they only reduce intake and increase excretion to achieve weight loss. Since all drugs have a certain degree of toxicity, after oral administration, they are absorbed into the bloodstream and detoxified by the liver, which increases the burden on the liver and can cause damage. Currently, the use of a number of weight-loss drugs, such as fenfluramine, has been banned in China because they contain ingredients that can cause certain heart valve dysfunctions.

Why does exercise sometimes lead to weight gain?

Many people have experienced this: they participate in weight loss exercises, such as aerobics, sit-ups, or using exercise equipment, with the goal of losing weight. However, after a month or two, not only does their appetite increase and their weight increase, but their waist and hip circumference also become larger! Why have they gained weight again?

The reason is that effective weight loss through exercise requires guidance from a professional fitness coach, a consistent increase in exercise volume, and consistent exercise time. Scientific measurements show that continuous jogging of over 20,000 meters is needed to burn body fat. In the initial stages of exercise, muscles gradually develop, but fat is not burned or reduced. This leads to weight gain and an increase in waist and hip circumference. When choosing exercise for weight loss, please be sure to do so under the guidance of a professional fitness coach and have the determination to persevere long-term—something many people find difficult to do.

If you can't consistently maintain your exercise routine, a sharp decrease in exercise intensity leads to a drastic reduction in the muscles' need for nutrients from the blood. However, the number of open capillaries supplying the muscles doesn't decrease, and excess nutrients (mainly carbohydrates) are converted into fat and stored in the areas supplied by these blood vessels. Since the number of fat cells is relatively fixed, but the volume of each fat cell is rapidly increasing, this subcutaneous fat feels firm to the touch.

Over a period of time, repeatedly increasing or decreasing exercise can cause fluctuations in weight. You might gain more weight, or you might gain and lose weight repeatedly before returning to your original level, which is detrimental to your health.