Studies have found that many cancers are related to obesity. Nowadays, more and more people are becoming obese. However, doing two things can easily achieve the effect of cancer prevention and weight loss.
Increased RiskCompared to those with normal weight, the risk for several cancers increases substantially for those who are obese or overweight:
- Endometrial cancer: The risk is seven times higher for those with severe obesity, and two to four times higher for those who are obese or overweight.
- Esophageal cancer (esophageal adenocarcinoma): The risk is 4.8 times higher for severely obese people and 1.5 to three times higher for obese or overweight people.
- Stomach cancer (gastric cancer): The risk is twice as high for obese people.
- Liver cancer: The risk is twice as high for obese or overweight people.
- Kidney cancer: The risk is twice as high for obese or overweight people.
- Pancreatic cancer: the risk is 1.5 times greater for obese or overweight people.
- Colorectal cancer: The risk is 1.3 times greater for obese or overweight people.
- Gallbladder cancer: The risk is 1.6 times greater for obese people and 1.2 times greater for overweight people.
- Meningioma: The risk is 1.5 times greater for obese people and 1.2 times greater for overweight people.
- Breast cancer (after menopause): The risk is 1.2 to 1.4 times greater for obese or overweight people.
- Thyroid cancer: The risk is 1.2 to 1.3 times greater for obese or overweight people.
- Multiple myeloma: The risk is 1.1 to 1.2 times greater for obese or overweight people.
- Ovarian cancer: The risk increases 1.1 times for every five-point increase in body mass index (BMI).
The most common type of cancer in obese men is colorectal cancer. In women, it's breast cancer after menopause.
Obesity and Cancer: Shared CausesDr. Chih Ying Liao, director of Radiation Therapy and Integrative Oncology Department at MOHW Taichung Hospital in Taiwan, pointed out that obesity is only one of the “manifestations” of these problems. Obesity is related to poor dietary habits, lifestyle, and metabolic factors, which themselves have the risk of promoting cancer.
For instance, frequently consuming fried foods, desserts, barbecued meats, and other unhealthy foods and not doing enough exercise are contributors to obesity, as well as cancer. After being fried, pan-fried, or grilled, meat will produce carcinogenic substances, such as heterocyclic amines and polycyclic aromatic hydrocarbons.
In particular, after being roasted or prepared through other high-temperature cooking methods, red meat tends to produce advanced glycation end products (AGEs), resulting in chronic inflammation and increasing the chance of cancer. If too many desserts are consumed, the sugar in them can bind to the protein molecules in the body and, after a series of reactions, can also form glycation end products.
Losing Weight can Reduce the Risk of CancerThe definition of obesity is different for everyone because of factors such as height, muscle mass, body shape, and so on. Body mass index (BMI) can be used as one basis for determining whether someone is obese, but it has limitations as well, since it doesn't account for muscle mass or waist circumference.
For most people, however, BMI is a good indicator of healthy bodyweight, since it's based on weight and height.
According to Liao, if someone has a BMI higher than 25, he or she is overweight; higher than 27 is mild obesity; and higher than 30 is moderate obesity. The higher the BMI, the stronger the cancer-causing factor of obesity, so attention should be paid to those with a BMI of higher than 27.
The CDC divides obesity into classes. People with a BMI from 30 to 35 are class 1, 35 to 40 are class 2, and 40 or higher are class 3, sometimes categorized as “severe” obesity.
Another simple way to determine obesity is to measure the waist circumference. This can also correlate with cancer risk. Women with a waist circumference of 32 inches or more and men with a waist circumference of 35 inches or more have a higher risk of developing cancer. Liao said the longer the waist circumference, the more serious the abdominal obesity and the higher the visceral fat content, meaning that the body is in a state of chronic inflammation with abnormal metabolic problems.
Therefore, obese people need to lose weight to reduce the risk of cancer. However, how much weight should they lose to be safe?
“Obese people who lose 5 percent of their current body weight will have reduced the risk of cancer,” Liao said.
In other words, a 150-pound person who loses 7.5 pounds will have a statistically relevant drop in their risk of cancer. He pointed out that although the ideal state is to reduce the weight to a BMI value of 25 or less, for many obese people, that would be difficult, and they might give up halfway.
Anti-Cancer Weight Loss MethodsThere are various ways to lose weight. However, using the wrong way or unsuitable ways to lose weight will make the body even more unhealthy.
According to Liao, exercise, a balanced diet, and consuming a lot of fruits and vegetables are ways that everyone can use to lose weight. In terms of diet, he recommended the Mediterranean diet, as well as eating fewer carbohydrates. People tend to eat too many carbohydrates, especially the over-processed carbs found in processed foods.
The Mediterranean diet is composed of vegetable-based meals, with high-quality proteins, whole grains, and healthy oils.
The Mediterranean DietThe Mediterranean Diet is already linked to healthy longevity, meaning researchers have found that people who follow this diet live longer and with fewer illnesses. The following are the key components of the Mediterranean diet.
Vegetables and FruitsThis diet is based on eating lots of vegetables with an appropriate quantity of fruits.
Vegetables and fruits are rich in dietary fiber, which can absorb toxins in the intestines and slow down the rise of blood sugar and the rate of blood glucose absorption. When the absorption of blood sugar becomes slower, the secretion of insulin and insulin-like growth factors will be reduced.
Fiber-rich foods can also balance and reduce the intake and absorption of fats and cholesterol, so that the body is less likely to accumulate visceral fat or produce excessive cholesterol. The more dietary fiber you consume, the easier it is to feel satiated. Fiber also promotes intestinal motility and helps with bowel movements.
Eating multicolored fruits and vegetables also provides access to a wide range of nutrients, including phytochemicals, which help the body resist oxidation and improve chronic inflammation.
High-Quality ProteinsThis diet includes eating plenty of legumes, seafood, eggs, white meat, and dairy products, such as Greek yogurt.
Whole GrainsBrown rice, black rice, quinoa, and oats are examples of healthy whole grains people eat on this diet.
Fish and Plant-Based FatsFish, olive oil, avocados, nuts, and seeds are the main sources of fats on the Mediterranean diet.
Train Muscles to Secrete Cancer-Fighting HormonesIn addition to adjusting our diet, exercise is also important. Liao said both aerobic exercise and muscle training should be taken into account.
Finally, during aerobic exercise, the heart rate should reach at least 130 beats per minute, which means that the person will be panting. You'll know you've reached the appropriate level of exertion if you can still talk, but singing is impossible.
This is the only way to effectively burn calories and improve metabolic problems.