Over the last 50 years, global obesity rates have reached such alarming levels that words like “obesity epidemic” and even “pandemic” are being used by respected journals and international bodies like the World Health Organization (WHO) as they try to raise awareness in the public and healthcare sectors. According to the World Health Organization, there are more than two billion adults considered overweight or obese using the Body Mass Index (BMI) method of classification. That’s nearly 40% of adults in the world. Mexico has even more staggering statistics, with about seven out of ten (70%) of all adults classified as being overweight or obese.
What’s more concerning is that the rate has been rising steadily for years. According to the World Obesity Federation, the worldwide prevalence of obesity nearly tripled between 1975 and 2016. What’s more, they estimate the figure of 770 million adults who were affected by obesity in 2020 is anticipated to exceed one billion by 2030 unless action is taken.
What do we know about obesity?
Let’s first define how a person gets to be classified as ‘overweight’ or ‘obese.’ The Body Mass Index, or BMI, is the most commonly used measure of obesity. It is computed by dividing a person’s weight in kilograms by the square of their height in meters. BMI scores will classify a person as:- Underweight – BMI under 18.5
- Healthy – BMI 18.5 to 24.9
- Overweight – BMI 25 to 29.9
- Obese (class 1) – BMI 30 to 34.9
- Obese (class 2) – BMI 35 to 39.9
- Obese (class 3) or Morbidly obese – BMI 40 or higher
What do we know now about how people become obese?
Firstly, the obesity epidemic isn’t just a matter of saying “people are eating too much, so they’re gaining weight.” Scientists have been studying the growing trend toward obesity for decades and have found many pieces of the puzzle. However, they still haven’t found a way to slow it down and are even further from finding how to reverse the change. It’s a complex health crisis that will require significant effort and resources to turn around. Here are some factors that seem to be contributing to the obesity epidemic.- Hormones like leptin play a key role in telling your body what to do. Leptin is a messenger hormone that tells your brain, “Hey, I’m full, stop eating.”
- Fats aren’t all bad. As we wrote in an earlier blog, when people hear the word “fat,” it immediately brings up negative emotions.
- Not all fats are created equal! There’s more than one kind of fat. Brown adipose tissue (BAT) is a kind of fat that actually helps you burn calories instead of storing them, unlike the usual white fat (white adipose tissue, or WAT), which the body uses to store energy for future use.
- WAT cells (adipocytes) in the body are constantly being formed and destroyed in what’s known as the adipocyte turnover. It’s a natural process of adipogenesis (creation of new fat cells) and apoptosis (cell death), as well as lipogenesis (fat storage) and lipolysis (fat breakdown).
- In obese individuals, the adipocyte turnover might be skewed, resulting in more WAT cells being created than destroyed.
- The amount of fat tissue in the body is regulated by a balance of several processes, including adipogenesis (creation of new fat cells) and apoptosis (cell death), as well as lipogenesis (fat storage) and lipolysis (fat breakdown).
- The brain has specific routes (pathways) that control messaging when we feel hungry and want to eat. Think of it like traffic signals for food inside your brain.
- Genetics plays a significant role. Research increasingly shows that there are genetic factors involved in obesity linked to specific genes. That’s why obesity often runs in families.
- Mutations of single genes might cause severe obesity that shows up in specific diseases such as Prader-Willi syndrome and Melanocortin 4 Receptor (MC4R) deficiency, which is one of the most common genetic disorders leading to obesity in both children and adults. However, there are thousands of tiny genetic differences that collectively influence BMI.
