May 11th every year is World Obesity Day. In recent years, an increasing number of studies have shown that obesity is closely related to the occurrence and development of various diseases, especially tumors. So, how did obesity and tumors become 'secret allies'? How can we prevent the occurrence of tumors through weight management? Today, experts in digestion, gynecology, oncology, and nutrition from Peking University People's Hospital will delve into the relationship between obesity and tumors, calling on everyone to pay attention to weight management and prioritize prevention. It's not just about being overweight, in short, it's a state of excessive accumulation of fat in the body, leading to weight exceeding the normal range. But obesity, a seemingly harmless "rich state", not only increases the risk of cardiovascular disease, diabetes and other metabolic diseases, but also quietly increases the probability of cancer. The International Agency for Research on Cancer (IARC) clearly pointed out that obesity is positively related to 13 types of cancer risks, including breast cancer, colorectal cancer, pancreatic cancer, endometrial cancer, etc. According to the World Health Organization's (WHO) 2023 report, the global number of overweight adults (BMI ≥ 25) has reached 2.6 billion, with 880 million being obese (BMI ≥ 30). In China, the situation is equally severe, with the adult overweight rate rising to 54.4% and the obesity rate reaching 18.9%, and this number continues to rise. The relationship between obesity and cancer cells is complex and intricate, involving multiple biological mechanisms and clinical manifestations. Obesity is not only an increase in weight, but also an abnormal proliferation of adipose tissue. Adipose tissue is an active endocrine organ that can secrete various cytokines and hormones, such as leptin, adiponectin, tumor necrosis factor alpha (TNF - α), etc. Under normal circumstances, adipose tissue plays an important role in maintaining metabolic balance and immune function in the body. But in obesity, the substances and functions secreted by adipose tissue become abnormal, leading to a series of metabolic abnormalities such as hormonal imbalance, chronic inflammation, insulin resistance, etc., providing a breeding ground for the growth of cancer cells. Under the activation of inflammatory response in obese state, the number of infiltrating macrophages in adipose tissue increases, leading to chronic low-grade inflammation. This inflammatory environment is conducive to the proliferation and metastasis of tumor cells. Inflammatory factors such as TNF - α (tumor necrosis factor alpha) and interleukin-6 (IL-6) quietly increase in the levels of obese individuals, which can accelerate the growth of tumor cells and the formation of blood vessels, paving the way for tumor spread. According to data from Cancer Research, the concentration of CRP (C-reactive protein) in obese individuals is twice that of normal weight individuals, and for every 1 mg/L increase in CRP, the risk of colorectal cancer increases by 25%. The imbalance of hormone levels and obesity are quietly changing the body's hormone levels. Estrogen can be said to be the "nutrient solution" for cancer cells. Obesity brings about an increase in estrogen levels, and the overexpression of estrogen in breast, uterus and other tissues is closely related to the occurrence and development of cancer, especially breast cancer and endometrial cancer. After menopause, obese women produce 50% -100% of their total body estrogen from adipocytes. The Lancet study shows that every 5 increase in body mass index (BMI) increases the risk of postmenopausal breast cancer by 12%. At the same time, obesity may also trigger insulin resistance, leading to increased secretion of insulin-like growth factor (IGF-1) that promotes tumor cell growth. This potent cell proliferation factor increases insulin levels in the blood by 2-3 times compared to normal individuals, allowing tumor cells to grow freely. According to the New England Journal of Medicine, among patients with pancreatic cancer, the mortality rate of those with BMI ≥ 30 is 40% higher than that of those with normal weight. Causing metabolic abnormalities and obesity is often closely related to metabolic syndrome, such as high blood sugar, high blood lipids, etc. These metabolic abnormalities can promote the occurrence and development of tumors through various pathways. For example, a high blood sugar environment can provide sufficient energy sources for tumor cells, allowing them to rapidly proliferate and pose a threat to health. Obesity can also affect the metabolism of fatty acids, generate excessive oxidative stress and free radicals, damage DNA, and increase the risk of gene mutations. These tumors are closely related to obesity and the increased risk of various solid tumors. Here are several common tumors associated with obesity. Obese individuals have a higher risk of developing colorectal cancer compared to those of normal weight. The chronic inflammation and metabolic abnormalities caused by obesity are its main mechanisms. Obesity is also a risk factor for the occurrence of colorectal adenomas, which are precancerous lesions of colon cancer. In addition, obesity increases the difficulty of colonoscopy examination, leading to an increased risk of missed diagnosis in colonoscopy screening for colon adenomas. Obesity in breast cancer is closely related to the occurrence of postmenopausal breast cancer. The increase in estrogen levels caused by obesity is one of the main reasons. Studies have found that the prognosis of breast cancer in obese people is poor, which may be related to the biological characteristics and treatment response of the tumor. Clinically, breast cancer in obese people is often more invasive and metastatic, and less sensitive to chemotherapy and radiotherapy. Obesity in liver cancer and pancreatic cancer is an important risk factor for nonalcoholic fatty liver disease (NAFLD), which is an important precursor of liver cancer. Obesity is also closely related to the occurrence of pancreatic cancer, which may be related to insulin resistance and chronic inflammation. Obese people have high incidence rate of liver cancer and pancreatic cancer, and poor prognosis, because these tumors are often found late and difficult to treat. Endometrial cancer is showing a trend of younger onset, and it is currently believed to be closely related to obesity. Adipose tissue increases aromatase activity, promotes the conversion of androgens to estrogens, forms a high estrogen microenvironment, and leads to endometrial hyperplasia and cancer. For young patients with fertility needs, relevant guidelines recommend using high-dose progesterone therapy to achieve complete tumor remission by antagonizing estrogen. However, obese patients often have lower tumor remission rates than non obese patients due to factors such as insulin resistance and chronic inflammation, and an increased risk of recurrence. Therefore, in clinical treatment, it is necessary to strengthen weight management to improve progesterone sensitivity, increase tumor remission rates, and pregnancy rates. Fleeting meat: an important part of cancer prevention. The relationship between obesity and tumors is not an exaggeration, but a scientifically verified fact. Obesity management is not only a matter of controlling weight, but also an important means of reducing tumor risk and improving health. Through reasonable dietary regulation and exercise, weight can be effectively controlled and the risk of tumor occurrence can be reduced. At the same time, regular physical examinations are also crucial, as they help detect potential health problems such as tumors early on. It is recommended to undergo a comprehensive physical examination once a year. A reasonable diet is key to a low calorie, low trans fat, low refined sugar, high quality protein, and high fiber diet. A low calorie, low trans fat, low refined sugar, high quality protein, and high fiber diet can help control weight and reduce the risk of tumor development. Encourage the main staple food to be whole grains and reduce excessive intake of refined white rice, flour, and pastries; Reduce the intake of fried and puffed foods; Eat more fresh fruits and vegetables, reduce the intake of high sugar fruits and high starch vegetables; Reduce the intake of sugary drinks. Reduce the intake of red meat and processed meat by prioritizing low-fat and high protein ingredients such as lean meat, skinless chicken breast, fish and shrimp. Red meat and processed meat are rich in saturated fatty acids and cholesterol, and long-term high intake can increase the risk of obesity and tumors. It is recommended to consume no more than 500 grams of red meat and no more than 150 grams of processed meat per week. At the same time, overweight and obese individuals should control their total energy intake. Generally, men are recommended to consume 1200-1500 calories per day, while women are recommended to consume 1000-1200 calories per day. Moderate exercise is essential. Physical exercise not only helps with weight loss, but also improves metabolic function and reduces inflammation levels. It is recommended to engage in at least 150 minutes of moderate intensity aerobic exercise per week, such as jogging, brisk walking, swimming, cycling, etc. Strength training can increase muscle mass, improve insulin sensitivity, increase basal metabolic rate, and help sustain calorie expenditure even when not exercising, in order to achieve weight control and prevent tumors. It is recommended to engage in 2-3 strength training sessions per week, such as weightlifting, push ups, sit ups, etc. Adjusting lifestyle: Smoking and alcohol consumption are the main risk factors for various cancers, including lung cancer, liver cancer, stomach cancer, etc. It is recommended to quit smoking and limit alcohol consumption. In addition, it is recommended to maintain a good psychological state and sufficient sleep to maintain physical health. Lack of sleep can affect metabolism and increase appetite; Long term exposure to high pressure can lead to increased secretion of stress hormones and promote fat accumulation. (New Society)