Obesity: A complete guide to this worldwide growing issue

All over the world, we hear that obesity is a growing issue. Yet, there is a growing market for plus-sizes and campaigns that being bigger is okay. However, what is obesity and how is it measured? What are the causes and treatments? What are the effects on our body, brain, and hormones? What are possible complications and tips to manage it?



What is obesity?

Obesity is a medical condition that is defined as having excess body fat that has accumulated to the point that it has negative effects on one’s health. Obesity occurs when someone consumes more calories than they burn and their body stores the excess calories (energy) as fat.

Obesity affects everyone- both upper and lower classes. In the early 20th century, obesity as considered a problem mainly in the first-world countries in the U.S. and Europe. In 1997, however, the World Health Organization declared that obesity was a global epidemic while the rates of obesity rose in Mexico, Brazil, Thailand, and China.

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Believe it or not, obesity has a long history throughout the world- and it wasn’t always considered bad. Throughout history, there has always been a decent number of people who have been poor and lacked good food, if they had food at all. Obesity was seen as a symbol of wealth and prosperity up until the 18th century. Once countries started to develop and food became more available, obesity started to rise all throughout the world. Initially, this increase in food had a positive effect- healthier and stronger population. After a while though, it turned into obesity.

During the 1930’s in the United States, life insurance companies would screen people for their body weight. In the 1950’s, doctors found the link between increasing rates of obesity and increased rates of heart diseases. In 2000, the number of people who were considered obese outweighed those who were considered underweight. In 2008, the U.S. spent $147 billion in medical costs due to obesity.



Classification of obesity

Body Mass Index (BMI) is the measurement used to classify obesity by the World Health Organization. It’s calculated by dividing someone’s weight (in kilograms) by their height (in meters). After that, divide the answer by their height again to get their true body mass index. Another way to calculate it is to take your weight in kilograms and divide it by your height in meters squared. BMI does have its limitations because it doesn’t distinguish between sex, age, bone mass, or muscle mass- all things which differ from individual to individual.

Generally, people are considered to be obese when their BMI is over 30kg/m. However, not all countries measure body weight the same way. For example, some East Asian countries use lower BMI values to classify obesity. About 13% of the adult population worldwide is classified as obese by these standards with a BMI of 30 or greater. According to the Centers for Disease Control and Prevention (CDC), in the U.S. it is estimated that about 34.9% of adults and 17% (12.7 million) teens and kids are considered obese.

Causes of obesity

A poor diet and a lack of exercise are the most common causes of obesity. However,, people can be genetically more prone to it. Obesity typically occurs when more calories are consumed than burned on a long-term basis.

Some typical causes of obesity are:

  • Diets that are high in fats and calories. Nutrition Fact LAbels try to help make people aware and steer people toward making better, healthier food choices, but that doesn’t always work. It’s been studied that obese people consistently under-report their food consumption compared to people with a healthy weight.
  • A lack of exercise leads to a sedentary and inactive lifestyle.
  • Not sleeping enough. A lack of sleep can lead to hormonal changes in the brain that make you feel hungrier and crave higher-calorie foods.
  • Genetics is a huge factor in obesity because your genetics are what affect how your body processes food into energy and how fat is stored. Our metabolism is a huge genetic factor. Another genetic factor is that some people have a gene that makes it difficult for them to lose weight while others have a gene that makes it near impossible for them to gain weight.
  • Age can be a cause of obesity. Growing older can lead to less muscle mass and slower metabolic rate which leads to a higher chance of gaining weight.
  • Certain medical conditions. Such as:
    • Polycystic ovary syndrome (PCOS) which causes an imbalance in female reproductive hormones and can cause one to overeat or not distribute the hormones correctly which can lead to weight gain.
    • Prader-Willi syndrome which is a rare condition that causes excessive hunger.
    • Osteoarthritis and other conditions that cause pain due to physical activity can lead to a sedentary lifestyle.
    • Hypothyroidism is a condition that means the thyroid is underactive. This causes the thyroid gland to not produce enough important hormones which can lead to a hormone imbalance and later on obesity.
    • Cushing’s syndrome is an excessive amount of cortisol in the system. Cortisol is our body’s main stress hormone and it has a lot to do with our blood sugar levels.
  • There are also social determinants that can cause obesity. For example, it’s easier to get obese if you live in a country where processed and sugary foods are sold on every street corner whereas it’s harder to become obese if you live in a situation in which you can’t afford much food, to begin with.
  • There are some gut bacteria, known as gut flora, that has been shown to differ between obese and lean humans. It’s thought that this gut flora affects the metabolic rate which in turn affects how we digest and distribute food within our bodies.


Diagnosis of obesity

While using a body mass index of 30 or more is the general measurement, there are other, more accurate ways to diagnose obesity, too. For example, looking at the body fat distribution such as hip-to-waist comparisons, measurement of fat around the waist, skinfold thickness, and screening tests like an ultrasound or a magnetic resonance imaging scan (MRI). A doctor can order blood tests to look at glucose and cholesterol levels, diabetes screen, thyroid tests, liver function tests, and heart tests such as an electrocardiogram.

Effects of obesity of the body

Obesity strains the entire body. Some people’s joints give out and they have major knee troubles or extreme back pain due to the amount of weight put on their joints. Other possible effects include high blood pressure, high cholesterol, heart disease, stroke, type II diabetes, and respiratory problems.

Effects of obesity on the brain

Our brains and obesity are closely linked. It was found that obesity caused food addictions. Weight gain may desensitize the brain’s pleasure it gets from eating sugary and fatty foods which makes us want to eat more in order to obtain that reward. One study in the Journal of Neuroscience studied women who drank a milkshake. The researchers saw the sugary drink activate the area of the brain known as the striatuma part of the brain that is a critical component of the motor and reward systems. Half a year later, the researchers brought back some of the same women, some of those who had gained some weight, and watched them drink a milkshake again. They found that the more weight that the women put on in within those six months, the less their brains responded to the milkshake.

It was found that being obese is a contributor to Alzheimer’s Disease and other conditions that increased the risk of dementia later in life. Obesity is associated with a decrease in total brain volume in middle-aged adults. Specifically visceral fat, also known as belly fat. It’s thought that the extra fat triggers inflammation which puts stress on the brain. Other studies have found that people with smaller brain volumes are at higher risk for dementia and do worse on cognitive tests. Hormones that are released by fat can impair memory according to some researchers. These hormones cause inflammation which also affects cognition.

A study published in the Journal of Brain, Behavior and Immunity suggests that the high-fat diet associated with the holidays may not only endanger one’s physical health but may also affect brain health. Researchers took two groups of mice- one ate 10% of their calories from saturated fats and the other group ate food that contained 60% fat. The 10% fat is what is considered a healthy diet versus the 60% fat which is considered a fast-food diet in people. After just four weeks, the “fast-food mice” were considered to be obese. However, they weren’t just obese- they also lost their synaptic markers in their hippocampus. These synaptic markers are made to clean the brain and to keep the neurons strong. This means that a high-fat diet and subsequent obesity damage the brain’s ability to remain strong and clean.



Effects of obesity on hormones

Obesity affects the hormones in many ways-, especially stress levels. Short-term stress can cause someone to lose their appetite. This is because a hormone, known as corticotropin is released. Signals to the adrenal glands, which trigger the production of adrenalin, are also sent.  However, chronic, long-term stress can do the opposite. This is because the hormone, known as cortisol, is released. Cortisol increases appetite. If the stress level doesn’t decrease, neither does the level of cortisol released and subsequently, the high level of appetite remains increased, as well.

Visceral fat, a.k.a. belly fat is thought to reduce brain size. This reduction causes the release of a unique set of hormones that impact the body in different ways.

Dieting is also through to change how the brain responds to stress. According to the Journal of Neuroscience, mice who lost 10%-15% of their body weight gained it back by eating when they were exposed to stressful situations- such as hearing sounds at nighttime. These weight-gaining mice were compared to a set of mice who were never placed on a diet in the first place.

Effects of obesity emotionally

In today’s society, it’s not easy to be obese because there is so much pressure to be skinny and as healthy as possible. Obesity can lead to sexual problems, shame, guilt, social isolation, lower work achievement. All of these, in turn, lead to depression. Studies have shown that obese people are 25% more likely to experience some sort of mood disorder- such as depression, compared to those who aren’t considered obese. The other psychological consequences of being or feeling obese can include anxiety, lowered self-esteem, and eating disorders such as bulimia, anorexia, and binge-eating. There is a strong correlation between suicidal thoughts/attempts and being obese. 

Treatment of obesity

Treating obesity isn’t as easy as it sounds. The biggest, most-effective treatment in most cases is a change in lifestyle and behavior. This means better food choices, a structured exercise program, and increased daily activity.



Another option is medical weight loss, this means taking prescribed weight loss medications in addition to lifestyle and behavioral changes. Typically these medications are only prescribed if there is a BMI of 27 or higher and the other treatments haven’t worked. These medications prevent the absorption of fat or they suppress appetite.

Weight loss surgery, also known as bariatric surgery, is an option that requires a full commitment to a lifestyle change from the patient. These surgeries work by limiting the amount of food one can eat comfortably and/or preventing the body from absorbing food and calories. People only qualify for surgery if they have a BMI of 40 or higher and after an extensive psychological evaluation. 

Complications from obesity

Obesity isn’t just weight gain, it’s also putting a strain on your entire body to function. Obesity is a major cause of several other medical issues. These include:

  • Type II diabetes
  • High blood pressure
  • Heart disease
  • High cholesterol
  • Fatty liver disease
  • Stroke
  • Certain cancers (such as breast cancer, colon cancer, and endometrial cancer)
  • Gallbladder disease
  • Infertility
  • Arthritis
  • Sleep apnea among other breathing problems

Management of obesity

While obesity is something that requires individual management, the World Health Organization tries to encourage governments to make their populations more aware of obesity and its health complications through public campaigns and schools.

The food industry is being encouraged to reduce the amount of fat and sugar in their processed foods as well as trying to make meal sizes smaller to help discourage overconsumption. Many people try to manage their weight by exercising often, eating right, managing stress, and trying their best to maintain their weight.

How has obesity affected you? Let us know in the comments below!

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