The unique advantages of exercise for weight loss and the various diseases caused by obesity.
8. The significance of exercise for weight loss
It's common to hear the statement: "Relying solely on exercise for weight loss is inefficient." Admittedly, for someone weighing 60kg, an hour of jogging might only burn 500 calories, resulting in a weight loss of just 1kg after a week of daily running. However, judging the effectiveness of exercise solely based on this is premature. Exercise offers many other benefits.
There is a difference between losing weight through exercise alone and losing weight through diet restriction alone. We conducted a comparative experiment using rats.
A rotating cage is installed in the enclosure, and the nocturnal rats enter the cage to exercise at night, running approximately 5-10 km per day. This exercise for 100 days can result in a weight loss of about 20%. During this period, food and water are provided freely. If the rats are deprived of food for two consecutive days and only given water, their weight can decrease by about 20%. This is known as extreme food restriction.
Both groups showed a 20% reduction in body weight, which is the same in that respect. However, there were significant differences in the underlying mechanisms. Firstly, the exercise-based weight loss group only lost fat; muscle mass remained unchanged or slightly increased. However, the calorie-restricted group lost not only fat but also muscle and liver weight.
True weight loss involves reducing only fat. If both fat and protein are reduced, the body will become weak. In this sense, exercise is the only true way to lose weight; relying on extreme dieting is harmful to health.
A particularly noteworthy issue is that while exercise increases glucose breakdown in the liver and fat cells during weight loss, extreme calorie restriction can actually decrease glucose breakdown, potentially leading to diabetes. For obese diabetic patients, extreme calorie restriction can worsen their condition. Conversely, because exercise accelerates glucose metabolism, it can, to some extent, improve diabetes.
The two basic measures for preventing and treating obesity are food restriction and exercise. However, this doesn't mean extreme food restriction. Generally, you should eat until you are 80% full, and then do some light exercise. This is the way to prevent and treat obesity. This method can also help manage diabetes.
9. Obesity can cause a variety of diseases.
In times of food scarcity, starvation was commonplace, making obesity a symbol of wealth and power. However, modern society presents a stark contrast. For example, obesity is decreasing in the upper classes of America while increasing in the lower classes. Therefore, contemporary American society considers being slim a symbol of status and intelligence. In a so-called era of abundance, the ability to control one's weight demonstrates good upbringing and strong self-discipline; conversely, obesity is seen as a result of ignorance and laziness. Looking around at the overweight people, it's difficult to buy clothes; they can't even look beautiful if they want to-it's truly lamentable.
Statistics show that obesity is linked to many diseases. Obese people are 10 times more likely to develop high blood pressure and 20 times more likely to develop heart disease than people of normal weight. Half of obese people have high blood pressure, 20% have diabetes, and 30% have heart disease. Furthermore, the mortality rate for obese men with diabetes is 3.8 times that of people of normal weight, and approximately twice that of those with appendicitis and gallstones. Due to excess abdominal fat, the risks during surgery are significantly increased. Chronic nephritis, cerebral hemorrhage, and coronary artery disease are also increased, and the risk of traffic accidents is 1.3 times higher than for people of normal weight. In addition, due to the effects of weight, the cartilage in the knee joint thins, and in women, it can lead to infertility and menstrual irregularities. Obesity can cause various dermatological diseases, such as hyperhidrosis, eczema, and dermatitis.
10. Diabetes and Exercise
Diabetes is a disease in which glucose is mixed in the urine. Symptoms include thirst, fatigue, frequent urination, and noticeable foam in the urine. Diabetes can be divided into two categories according to its cause: one is insufficient insulin secretion from the pancreatic β-cells, which is childhood diabetes; the second is adult-onset diabetes, where although insulin secretion is normal, there is a problem with the main target of this hormone-muscle and adipose tissue, that is, the activity of insulin is reduced.
Insulin is a hormone that transports glucose from the blood to muscle and fat cells. When insulin levels decrease, or even if there is a certain amount but it cannot react with muscle and fat cells, glucose cannot enter the cells, and the amount of glucose in the blood and urine does not decrease; in other words, the amount of glucose in the blood and urine increases. Since glucose cannot be removed and delivered into cells, energy cannot be released. No matter how much glucose increases in the blood and urine, it will not be converted into energy.
Normally, 100ml of blood contains 80-100mg of blood glucose, but it can increase to 160mg immediately after a meal, although it returns to its original value after 3 hours. In patients with diabetes, blood glucose levels do not decrease regardless of how many hours have passed after a meal.
When you exercise, blood flow to the capillaries in your muscles increases, and the muscles continuously absorb glucose. The entry of glucose into the muscles during exercise is largely independent of insulin. Therefore, even if insulin levels are insufficient, appropriate exercise can lower blood sugar. Furthermore, exercise makes it easier for insulin to react with muscle and fat cells. Although the exact mechanism is not fully understood, practical experience shows that the amount of glucose entering the muscles increases after exercise, and muscle and fat cells react more readily with insulin, thus making it possible for exercise to improve diabetes.
As a treatment for diabetes, insulin is administered when insulin is insufficient. There are also medications that promote insulin secretion and those that enhance the action of insulin in muscles and fat cells. Exercise is similar to this medication, or rather, a more effective method for preventing and treating diabetes. However, strenuous exercise should be avoided. Because insulin promotes glucose uptake and fat synthesis in fat cells while inhibiting fat breakdown within them, diabetes with low insulin response can easily lead to fat breakdown. In such cases, very strenuous exercise can cause a sharp increase in blood fatty acids, potentially leading to heart problems such as arrhythmia. Therefore, it is best to engage in gentle exercise tailored to one's physical condition.