Being overweight, which results in 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. Even if the analyzes are normal, the danger is already there.

Over the past decades, the average body weight of the population has increased dramatically, that is, more and more adults have a body mass index (BMI) over 25.

Remember 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 they is obese if this index is equal to or greater than 30.

There is no longer any doubt that this increase in the number of overweight people is responsible for a large proportion of the chronic diseases that currently affect our society.

A surplus of fat in the tissues is a completely abnormal condition which disturbs the homeostatic balance of the organism and favors the development of several pathologies. Type 2 diabetes, cardiovascular diseases as well as several types of cancer are diseases that preferentially affect overweight people and drastically reduce their quality and life expectancy.

Overweight, yet seemingly healthy

Surprisingly, the researchers observed that a small proportion of obese people did not show the characteristic disturbances of the metabolism of overweight. These people have normal blood sugar and insulin levels, are not hypertensive, and have a normal blood lipid profile. As a result, despite being obese, they do not appear to be more at risk of type 2 diabetes and heart disease than the normal weight population. But are these people also protected against cancer?

To answer this question, researchers examined the presence of adenomatous polyps (adenomas) in the colon of 18,000 people aged 40 on average. These adenomas are precancerous lesions that gradually progress to colorectal cancer and therefore represent a very precise marker of the risk of being affected by this disease in the coming years.

They observed that people who were overweight, but whose metabolism was normal, had a 17% greater risk of developing adenomas than people of normal weight, this risk rising to 45% for obese people. For higher grade adenomas, that is to say which are at greater risk of progressing to cancer, the increase is even more marked, reaching 50% for overweight people and 60% 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 cancers than people of weight. normal.

75% less risk of colon cancer

We have a fatalistic attitude towards being overweight, as if it were normal and inevitable to accumulate pounds with age. In fact, this weight gain is much more a reflection of our poor eating habits and reduced levels of physical activity that come with aging, often in response to the busy schedules of modern life that leave little time for worrying about one’s health. health.

Yet the cancer prevention potential of maintaining a normal body weight is quite extraordinary and it is definitely worth avoiding weight gain throughout adulthood.

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, a moderate consumption of red meats and regular physical exercise, this are 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; 73:4020-7

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