Find the nutrition column of Stéphane Besançon, nutritionist and director of the NGO Santé Diabète in Bamako, Mali. This week, he talks to us about weight.
Is there a tool that allows you to know if your weight is normal or not?
We know that there is often a difference between the vision we have of our weight and the reality of it. You can have a normal weight with regard to medical thresholds and still think that you are too thin. Conversely, we can feel that his weight is medically abnormal even though socially, it is accepted, even valued. To have an objective and scientific orientation, which takes into account medical recommendations to ensure good health, there is an index called the Body Mass Index which is better known by its acronym BMI. In adults, BMI is calculated by dividing their weight (in kilograms) by their height squared (in meters).
Once the calculation has been carried out, it suffices to report the result on a scale:
- Below 18.5 we speak of thinness, the person is therefore too thin
- Between 18.5 and 25, we have a normal weight
- Between 25 and 30, the person is overweight
- Above 30, this is moderate obesity; over 35 severe obesity and over 40 very severe obesity
Does this tool alone allow us to know if our weight presents a risk to our health?
Not completely, because we know that some people, such as athletes, can have a height and weight that will classify them as overweight or obese. An athlete who is 1.85 and weighs 120 kg will have a BMI of 35 corresponding to severe obesity. However, this person has a body composition which is made up mainly of muscles and which does not present a risk to his health.
If your BMI gives you a result of overweight or obesity, or if your weight is normal, but you have a belly then it is also absolutely necessary to measure your waist size. To measure this waistline, it’s very simple. You have to bring a tape measure, stand up with your feet together, your arms at your sides. The tape measure should be passed halfway between the last palpable rib and the bone at hip level. It is important to take this measurement when you have finished exhaling. The result of this measurement must be: Less than 94 cm for men and less than 80 cm for women.
Why is this waist measurement so important?
There are two kinds of fat distribution when you are overweight or obese:
- gynoid obesity which is characterized by a distribution of fat rather on the thighs and buttocks and
- android obesity which is characterized by a distribution of fat in the abdominal area, that is to say in the belly.
These two types of fat do not play the same role in the risk of developing diabetes or cardiovascular disease at all. It has been shown that the higher the amount of abdominal fat, the greater the risk of metabolic disorders – and therefore the risk of cardiovascular disease and diabetes – increases. The waist circumference is therefore extremely important as an indicator of visceral adiposity and therefore of the amount of abdominal fat in a person and therefore of his risk of developing diabetes or cardiovascular diseases.
Should we give up the body mass index?
No, because overall, excess weight is a major risk factor for diseases such as diabetes, high blood pressure, cerebrovascular accidents (stroke) and certain types of cancer. It also worsens joint problems such as osteoarthritis of the knees and hips. It is therefore important to have a first global indicator on the weight. But as we saw previously, the abdominal perimeter gives a more precise prediction of the risk of diabetes and cardiovascular diseases. The ideal is therefore to advise to combine these two measures (BMI and abdominal perimeter) in order to know our situation, our risk and the changes in lifestyle to operate in order to bring these indices back to normal values. For this, we know that it is necessary to practice a physical activity with:
- i.e. 30 minutes of moderate physical activity per day (such as walking for example)
- or 75 minutes per week of sustained intensity activities such as running, cycling or swimming.
- It is also necessary to adopt a diversified and balanced diet which is rich in fruits, vegetables while minimizing the consumption of fats, salt and sugars.
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