Characteristics of people prone to obesity and the relationship between obesity and high blood lipids, coronary heart disease, and hypertension

Who is prone to weight gain? Is obesity related to genetics?

Through clinical observation and analysis, we know that the following conditions can easily lead to obesity.

Athletes and actors who stop exercising, training, or significantly reduce their physical activity for any reason will experience rapid weight gain, sometimes even becoming obese. Some people become obese due to reduced activity levels or even bed rest caused by illnesses such as tuberculosis, nephritis, or hepatitis. In particular, patients with mental disorders often experience weight gain and obesity due to the use of antipsychotic medications, which can lead to drowsiness, increased appetite, and lethargy.

Clinical observations have also revealed a higher incidence of obesity among people who enjoy sweets and oily foods, as well as those who snack between meals. This is because sweets, oily foods, and snacks are high in carbohydrates and fats, providing a significant amount of calories. Frequent alcohol abuse also increases the risk of obesity. While small amounts of alcohol are harmless, excessive drinking generates a large amount of calories, which are then converted into fat and stored, leading to weight gain.

Obesity is common during pregnancy and postpartum. After becoming pregnant, women experience hormonal changes, coupled with the consumption of large amounts of nutritious food and reduced physical activity, especially in the later stages of pregnancy when the body becomes heavy and movement is difficult, leading to significant weight gain. Postpartum weight gain is now even more prevalent. The traditional Chinese practice of "sitting the month" (postpartum confinement) involves consuming large amounts of high-protein, high-calorie foods to compensate for the physical exertion and blood loss during childbirth, while also limiting physical activity. This excess nutrition leads to calorie accumulation, which is deposited in the body as fat, resulting in obesity.

In middle age, people are at their most vigorous, with ovarian or testicular function remaining strong and sex hormone secretion levels remaining quite high. This directly relates to the metabolism of protein and fat in the body. People have a strong appetite and eat a lot, while their activity level is significantly reduced compared to when they were younger. This leads to an imbalance between "income and expenditure," with excess calories being stored as fat, eventually resulting in obesity.

Weight is influenced by genetic factors to some extent, with 40-60% of obese individuals having a family history of obesity. Some studies have found that if one parent is obese, half of their children will also be obese; if both parents are obese, two-thirds of their children will be obese; and if both parents are thin or of normal build, only 10% of their children will be obese. The correlation between weight is stronger between identical twins and between fraternal twins or twins, especially among identical twins separated at a young age and raised in different environments; the correlation between their weights still exists. We found no significant correlation between the weight of adopted children and their adoptive parents, but a close relationship exists between their weight and that of their biological parents.

Obesity is not only hereditary in terms of obesity itself, but also in the location of fat distribution. For example, a study of 18 obese mothers who had 12 obese daughters found that the distribution of fat in the mothers and daughters was very similar.

There is also a close link between bone structure and obesity. Only 3% of men and 5% of women with slender bones are overweight, while 37% of men and 67% of women with broad bones are overweight. Among obese women, 52% have a strong, athletic build, compared to only 1.5% of women of normal weight. This indicates that people with broad bones and strong, athletic builds are more prone to obesity.

Scientists have discovered a genetic pattern of obesity in laboratory animals, mice and rats. The distribution of adipose tissue and the age of onset of obesity in genetically obese mice are distinctive. Furthermore, they found that the obesity in these mice cannot be explained by a good appetite or large food intake.

What is the relationship between obesity and hyperlipidemia, coronary heart disease, and hypertension?

Hyperlipidemia is a condition characterized by excessively high levels of lipids in the blood. Blood lipids include cholesterol, triglycerides, and phospholipids. Obese patients not only have increased body fat but also significantly elevated blood lipid levels, particularly triglycerides, free fatty acids, and cholesterol, which are often higher than normal.

The mechanisms by which obesity can cause or worsen hypertriglyceridemia are complex, but in most cases, it's primarily due to a strong and uncontrollable appetite, coupled with improved living standards leading to increased consumption of fatty foods, and a reluctance to engage in physical activity after becoming obese. Obese individuals not only accumulate large amounts of body fat but also have elevated blood lipids; obese patients with a genetic predisposition often also have hyperlipidemia, and even individuals with normal weight in their family may have hyperlipidemia. Clinical trials have shown that when weight is reduced by restricting dietary intake or engaging in exercise and physical activity to increase calorie expenditure, common blood lipid levels also decrease. This indicates a close relationship between obesity and hyperlipidemia.

It's worth noting that you shouldn't lower your cholesterol too much. A study by Japanese scholars on the relationship between cholesterol and survival rate among the elderly in nursing homes demonstrated that it wasn't the group with the lowest cholesterol that had the highest survival rate; in fact, the group with the lowest cholesterol also had the lowest survival rate. Furthermore, cancer patients with hypolipidemia have a higher survival rate than those with normal or hyperlipidemia.

Coronary heart disease (CHD) is short for coronary atherosclerotic heart disease, which refers to heart disease caused by atherosclerosis of the coronary arteries that supply blood to the heart, leading to myocardial ischemia and hypoxia. It is a common disease among middle-aged and older adults.

Obesity is closely related to coronary heart disease (CHD). The incidence and mortality rates of CHD are significantly higher in obese patients than in non-obese patients. Some data indicate that the incidence of CHD in obese individuals is 5:1 compared to lean individuals, and the mortality rate can exceed 30-40%. Some scholars suggest that a weight gain exceeding 30% of ideal body weight is a warning sign of developing CHD within 10 years, and that CHD in obese patients is more difficult to treat and poses a greater risk than in non-obese patients.

Obesity can easily lead to hyperlipidemia, atherosclerosis, and diabetes, all of which are risk factors for coronary heart disease. The pathogenesis of coronary heart disease in obese patients mainly includes the following aspects: ① Exceeding the standard weight increases the workload on the heart and causes hypertension. ② Coexisting lipid metabolism abnormalities and hyperlipidemia caused by high-calorie diets lead to coronary atherosclerosis and myocardial fat deposition, ventricular wall thickening, and decreased myocardial compliance. ③ Obese patients reduce physical activity, weaken or fail coronary collateral circulation, and decrease the heart's compensatory capacity.

Therefore, it can be said that preventing obesity is, in a sense, also preventing coronary heart disease.

The incidence of hypertension is significantly higher in obese individuals than in non-obese individuals, ranging from 22.3% to 52%. Moreover, the incidence of hypertension increases exponentially with the degree of obesity. Some statistics show that when overweight is less than 10%, the incidence of hypertension is 10.3%; when overweight is 10-20%, the incidence is 19.1%, almost doubling; and when overweight is 30-50%, the incidence can reach as high as 56%. This means that a moderately obese person is more than five times more likely to develop hypertension than someone less than 10% overweight, and more than twice as likely as someone mildly obese. In contrast, the incidence of hypertension is only 5.5% in people with below-standard weight. Clearly, the greater the obesity, the higher the incidence of hypertension.

Obesity contributes to hypertension for the following reasons: ① Hemodynamic changes, such as increased oxygen gradient between arteries and veins, especially during activity; increased cardiac output and blood volume. ② Endocrine changes, such as increased adrenaline levels, imbalance in the renin-angiotensin-aldosterone system, hyperinsulinemia, increased thyroid hormone levels, elevated adrenaline concentration (exceeding 30% of that in non-obese individuals of the same age), elevated aldosterone, and increased norepinephrine secretion, all of which can lead to elevated blood pressure. ③ Environmental factors, such as reduced physical activity, lower energy expenditure, increased food intake, and excessive sodium intake in obese individuals. ④ Genetic factors, including a family history of obesity and hypertension, especially idiopathic obesity.