Excess body fat is associated with a significant increase in the risk of being affected by at least seven types of cancer, including colon cancer.
This increased risk is also observed in overweight people, even if their metabolism is normal.
In recent decades, the average body weight of the population has increased dramatically. Someone is considered to be overweight when their body mass index (BMI) is greater than 18. Recall that the BMI can be easily calculated by dividing the weight (in kg) by the height squared (in m2). If the BMI is between 25 and 29, the person is overweight, while obese if this index is equal to or greater than 30. This increase in the number of overweight people is responsible for a high proportion of chronic diseases that currently affect our society.
A surplus of fat in the tissues is a completely abnormal condition that disturbs the homeostatic balance of the body and promotes the development of several pathologies. Type 2 diabetes, cardiovascular diseases as well as several types of cancer are diseases which preferably strike overweight people and drastically reduce their quality and their life expectancy.
Overweight but all health markers are green
Surprisingly, the researchers observed that a small proportion of obese people did not present the characteristic disturbances of overweight metabolism. These people have normal blood sugar and insulin levels, are not hypertensive and have a normal blood lipid profile.
As a result, despite their obesity, they do not appear to be at greater risk to be affected by type 2 diabetes and heart disease than the normal weight population. But are these people also protected against cancer?
Overweight: increased risk of colon cancer of 45%
To answer this question, researchers looked at the presence of adenomatous polyps (adenomas) in the colon of 18 people aged 30 years on average. These adenomas are precancerous lesions that progressively progress to colorectal cancer and therefore represent a very precise marker of the risk of being affected by this disease over the next few years.
They observed that people who were overweight but had normal metabolism had 17% more risk of developing adenomas than people of normal weight, this risk rising to 40% for obese people. For higher grade adenomas, that is, adenomas that are at greater risk of progressing to cancer, the increase is even more marked, reaching 45% for overweight people and 50% for obese people.
In other words, even when the overweight person is in apparent good metabolic health, without showing warning signs of diabetes, hypertension or heart disease, he remains at a higher risk of developing certain diseases. cancers than people of normal weight.
Healthy weight: 73% of cancers of the colon could be prevented
We have a fatalistic attitude towards being overweight, as if it were normal and inevitable to accumulate pounds with age. In reality, this weight gain is much more a reflection of our poor eating habits and the reduced levels of physical activity that accompany aging, often in response to the busy schedules of modern life that leave little time to worry about.
Yet the potential for preventing cancer by maintaining a normal body weight is quite extraordinary and it is definitely worth avoiding weight gain throughout adult life.
In the case of colon cancer, it is estimated that if the maintenance of a normal weight is combined with a diet rich in certain fruits and vegetables, with a moderate consumption of red meats as well as regular physical exercise, up to 75% of colon cancers that could be prevented.
Yun KE et al. Impact of body mass index on the risk of colorectal adenoma in a metabolically healthy population. Cancer Res, 60: 4020
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