1. Diabetes
Obesity is closely linked to diabetes. A survey of over 310,000 individuals across 14 provinces and municipalities in China revealed that the prevalence of diabetes in the general population was 0.26%, while among overweight individuals it reached 2.82%—more than ten times higher.Individuals with obesity consume more food than their bodies require. Excessive eating stimulates the pancreas to secrete excessive insulin, leading to hyperinsulinemia. Since the cells of obese individuals are insensitive to insulin, this further promotes insulin secretion, increasing the burden on the pancreas. Pancreatic cells proliferate and hypertrophy, which over time can lead to pancreatic failure and the onset of diabetes.Additionally, obesity often coexists with hyperlipidemia, frequently causing hyperlipidemic metabolism and elevated free fatty acids, which exacerbate glucose metabolism disorders and increase susceptibility to diabetes.
2. Hypertension
Obesity is a risk factor for the onset and progression of hypertension. A study of middle-aged and elderly individuals revealed that the prevalence of hypertension was 7.55% among those with a body mass index (BMI) below 20, 20.26% among those with a BMI between 24 and 26, and reached 36.89% when BMI exceeded 28.Obesity leads to a substantial increase in adipose tissue, necessitating higher blood volume and cardiac output to meet bodily demands. Prolonged cardiac overload causes left ventricular hypertrophy and elevated blood pressure. Additionally, obese individuals often exhibit hyperinsulinemia, where insulin promotes sodium reabsorption in the distal renal tubules, leading to sodium retention and hypertension.Additionally, obese individuals exhibit heightened adrenal cortex activity, increased cortisol conversion rates, and enhanced hydroxylation of corticosterone and dehydroepiandrosterone, all contributing to elevated blood pressure. Thus, obesity represents a significant risk factor for hypertension.
3. Arteriosclerosis and Coronary Heart Disease
Survey data indicate that the prevalence of coronary heart disease is 4.72% among individuals with a body mass index (BMI) below 20, 9.91% among those with a BMI of 24–26, and as high as 16.51% among those with a BMI exceeding 28.Obesity often involves hypertriglyceridemia, which contributes to atherosclerosis. Factors such as excess body weight, increased body surface area, excessive adipose tissue, and heightened cardiac workload (including myocardial overload due to fat deposition within and around the heart) can cause myocardial ischemia and hypoxia. Reduced physical activity in obese individuals further weakens or impairs coronary collateral circulation.All these factors can contribute to atherosclerosis and coronary heart disease. 4. Respiratory Insufficiency Clinically termed the obesity-hypoventilation syndrome, also known as hypoventilation syndrome.In severely obese individuals, excessive fat in the chest and abdominal walls restricts respiratory movement, resulting in shallow breathing and reduced expiratory volume. This decreases functional residual capacity, keeping the lungs in a near-exhalation position. The reduced tidal volume diminishes alveolar ventilation, limiting gas exchange and causing carbon dioxide retention. Arterial oxygen saturation drops, potentially leading to cyanosis.Chronic hypoxia may trigger secondary polycythemia, accompanied by increased blood viscosity, which heightens circulatory resistance and cardiac workload. This progression can lead to pulmonary hypertension and chronic cor pulmonale.
5. Fatty Liver
Obesity can induce hepatic steatosis, causing hepatomegaly.In obese individuals, prolonged high-carbohydrate, high-fat diets combined with hyperinsulinemia cause the liver's triglyceride synthesis rate to vastly exceed its transport capacity. Alternatively, impaired triglyceride removal by very-low-density lipoproteins may occur, leading to triglyceride accumulation within the liver and resulting in fatty liver disease.