According to the World Health Organization (WHO), theobesity is characterized by “an abnormal or excessive accumulation of body fat which can be harmful to health”.

Basically, obesity is the result of consuming too much calories relative to energy expenditure, for several years.

Obesity must be distinguished from being overweight, which is also overweight, but less significant. For its part, themorbid obesity is a very advanced form of obesity. It would be so damaging to health that it would lose 8 to 10 years of life⁵⁴.

Diagnose obesity

We cannot rely solely on the weight a person to determine if they are obese or overweight. Different measures are used to provide additional information and to predict the impact of obesity on health.

• Body mass index (BMI). According to the WHO, this is the most useful, albeit approximate, tool for measuring overweight and obesity in an adult population. This index is calculated by dividing the weight (kg) by the size squared (m²). We speak of overweight or overweight when it is between 25 and 29,9; obese when equal or exceed 30; and morbid obesity if it equals or exceeds 40. The healthy weight corresponds to a BMI between 18,5 and 25. Click here to calculate your body mass index (BMI).

  Remarks

  – The main disadvantage of this measuring tool is that it does not give any information on the distribution of fat reserves. However, when fat is concentrated mainly in the belly region, the risk of diabetes and cardiovascular disease is higher than if it is concentrated in the hips and thighs, for example.

  – In addition, the BMI does not make it possible to distinguish between the mass of os, muscles (muscle mass) and fat (fat mass). Therefore, BMI is imprecise for people with large bones or very muscular builds, such as athletes and bodybuilders;

• The waistline. Often used in addition to the BMI, it can detect excess fat in the abdomen. It is aboutabdominal obesity when the waist circumference is greater than 88 cm (34,5 in) for women and 102 cm (40 in) for men. In this case, the health risks (diabetes, hypertension, dyslipidemia, cardiovascular disease, etc.) are considerably increased. Click here to find out how to measure your waistline.
• The waistline / hip circumference ratio. This measurement gives an even more precise idea of ​​the distribution of fat in the body. The ratio is considered high when the result is greater than 1 for men, and greater than 0,85 for women.

Researchers are working on developing new tools for measuring excess fat. One of them, called fat mass index ou IMA, is based on measurement of hip circumference and height¹⁶. However, it has not yet been proven and is therefore not used medicinally at the moment.

To assess the existence of risk factors for disease, a blood test (especially the lipid profile) gives valuable information to the doctor.

Obesity in numbers

The proportion of obese people has increased over the past 30 years. According to the World Health Organization (WHO), the prevalence of obesity has taken epidemic proportions worldwide. The increase in average weight is observed in all age groups, in all socio-economic groups¹.

Here is some data.

• In the monde, 1,5 billion adults aged 20 and over are overweight, and at least 500 million of them are obese^2,3. Developing countries are not spared;
• Au Canada, according to the most recent data, 36% of adults are overweight (BMI> 25) and 25% are obese (BMI> 30)⁵ ;
• To United States, about a third of people aged 20 and over are obese and another third are overweight⁴⁹ ;
• En France, nearly 15% of the adult population is obese, and about a third is overweight⁵⁰.

Multiple causes

When we try to understand why obesity is so prevalent, we find that the causes are multiple and do not rest solely on the individual. The government, municipalities, schools, the agri-food sector, etc. also bear a share of responsibility in the creation of obesogenic environments.

We use the expression obesogenic environment to describe a living environment that contributes to obesity:

• accessibility to foods rich in gras. At salt and sucre, very caloric and not very nutritious (junk food);
• way of life sedentary et stressful ;
• living environment not very conducive to active transportation (walking, cycling).

This obesogenic environment has become the norm in several industrialized countries and is found in developing countries as people adopt a Western way of life.

People whose genetics make it easier to gain weight are more likely to fall victim to the obesogenic environment. However, gene-related susceptibility cannot lead to obesity on its own. For example, 80% of Pima Indians in Arizona today suffer from obesity. However, when they followed a traditional way of life, obesity was much rarer.

Consequences

Obesity can increase the risk of many chronic diseases. Health problems would begin to manifest after about 10 years excess weight⁷.

Risque greatly increased¹ :

• type 2 diabetes (90% of people with this type of diabetes have a problem with being overweight or obese³);
• d’hypertension ;
• gallstones and other gallbladder problems;
• dyslipidemia (abnormal lipid levels in the blood);
• shortness of breath and sweating;
• sleep apnea.

Risque moderately increased :

• cardiovascular problems: coronary artery disease, cerebrovascular accidents (stroke), heart failure, cardiac arrhythmia;
• osteoarthritis of the knee;
• of gout.

Risque slightly increased :

• certain cancers: hormone-dependent cancers (in women, cancer of the endometrium, breast, ovary, cervix; in men, prostate cancer) and cancers related to the system digestive (cancer of the colon, gallbladder, pancreas, liver, kidney);
• decreased fertility, in both sexes;
• of dementia, low back pain, phlebitis and gastroesophageal reflux disease.

The way in which fat is distributed over the body, rather in the abdomen or hips, plays a decisive role in the appearance of diseases. The accumulation of fat in the abdomen, typical ofandroid obesity, is much more risky than the more uniform distribution (gynoid obesity). Men have on average 2 times more abdominal fat than premenopausal women¹.

Of concern, some of these chronic diseases, such as type 2 diabetes, are now occurring in theadolescence, given the growing number of overweight and obese young people.

Obese people have a poorer quality of life by aging⁹ and life expectancy shorter than people who are at a healthy weight^9-11 . Moreover, health professionals predict that today’s young people will be the first generation of children whose life expectancy will not exceed that of their parents, mainly because of the increasing frequency ofobesity infant⁵¹.

Finally, obesity can become a psychological burden. Some people will feel excluded from society because of the standards of beauty offered by the fashion industry and the media. Faced with the difficulty of losing their excess weight, others will experience great distress or anxiety, which can go as far as depression.