No matter who you are or where you live, your weight has a direct impact on your physical, mental, and emotional health. But, as it turns out, how much we weigh is not necessarily caused only by what we eat and how much exercise we participate in on a daily basis. As more people around the world are diagnosed as overweight or obese every single year, understanding the many factors that lead to excessive weight gain has never been a more critical task.
Despite being considered a serious medical condition, many people view obesity as a condition purely brought on by a person’s actions and decisions. Deeply tied to genetic, socioeconomic, and environmental factors, it is true that certain people are significantly more likely to gain weight and become overweight and obese. With a large amount of societal pressure and stigma against weight gain, it can be incredibly difficult for people to get accurate information about why they may be more likely to gain weight than others.
Looking to tackle this issue head one, we want to share some of the most common factors and predispositions that can increase your risk of experiencing obesity during your lifetime. With many of these factors being completely out of a person’s control, finding ways to better support improved education and support for people with obesity should be our top priority in the global mission to reduce the health burden of obesity.
Obesity is defined as the development of excess adipose (fat) tissue throughout the body that is connected to an increased risk for poorer health outcomes. Often measured using the body mass index (BMI), a person with a BMI of 30 or greater is considered to be obese.
With the many improvements in modern convenience and a decreased need for extensive labour, the prevalence of obesity has been on the rise for the past few decades. According to the World Health Organization (WHO), the rate of obesity in adults has increased from 6.3% in the 1990s to 13.2% in 2016 — with the number only rising in each following year¹. Now reaching epidemic levels, millions of people pass away from health complications associated with obesity every single year².
As the number of people living with obesity continues to climb, more research is being done to better understand the true nature of the disease. Working to break down the stigma against those who find themselves able to gain weight quite easily and quickly, learning more about the non-controllable factors that lead to obesity is an essential starting point for finding more sustainable treatment options for those living with the disease.
As a result of the increased concern about the prevalence of obesity, researchers have begun to explore what factors can predispose a person to becoming overweight. While there are a multitude of different causes of obesity, here are some of the less-known reasons why a person may be at an increased risk of becoming obese:
Our genetics are proteins that code for our unique physical traits. In addition to this, they also can play a role in the development of many different diseases. With some diseases being purely genetic in nature (meaning they are hereditary, being passed on from parent to child), research has shown that there is a complex relationship between our genetic code and the risk of becoming overweight. While it is not likely that genetic predisposition to obesity is the primary cause for its significant rise in recent decades, it is worth noting that researchers have been able to identify unique genetic variants that are associated with the development of obesity³. But, just because you carry the specific gene variant to have an increased predisposition to obesity does not mean you will gain a significant amount of weight out of nowhere. Eating a healthy and balanced diet and regularly exercising are great ways to reduce the risk of becoming overweight, no matter what your genetic code says!
Across the world, the nation with the highest number of citizens living with obesity in the United States of America. With more than 40% of the American adult population diagnosed as obese, living in America dramatically increases your risk of becoming obese compared to other areas of the world4. Other countries that also struggle with high levels of obesity include Saudi Arabia, Egypt, Libya, Iraq, and Turkey⁴.
For children growing up in these types of environments, it is very easy for them to adapt their lifestyles to the types of food that they are exposed to. This, in turn, can make switching to healthier food more of a psychological and mental struggle later in life, which impacts a person’s ability to maintain a healthy weight.
Contrary to popular belief, overeating is not actually caused by greed and poor self-control and willpower. Hunger, which is the feeling that drives us to eat, is actually a physiological response to various hormones in our body. Able to be triggered at any time depending on a variety of factors, hunger and intense food cravings are caused by three primary hormones:
Leptin — An appetite-suppressing hormone created by adipose tissue. It is very common for people with excess fat tissue to develop a resistance to leptin, which can lead to overeating⁵.
Ghrelin — Made from enteroendocrine cells in our GI tract, ghrelin is often referred to as the “hunger hormone”. When released, ghrelin induces hunger, even after eating a large meal⁶.
Insulin — Created in the pancreas, insulin is responsible for regulating our blood sugar levels after eating⁵.
When any of these hormones are out of balance, it is very easy for the body to create a hunger response even when we do not require any additional energy for our activities. With many people living with hunger-hormone imbalances, more people are being driven to overeat and gain weight.
Because leptin is made from adipose tissue, it is incredibly common for people who carry excess weight to have higher than average levels of leptin throughout their bodies. And while it would seem that increased leptin would lead to a decrease in appetite, it seems that our bodies are quick to develop a natural resistance to the hormone. When exposed to leptin at high levels, our brain becomes less receptive to it, which in turn reduces the amount that leptin can suppress our appetite. In this way, a vicious cycle is created: our brain triggers hunger, we overeat (increasing the amount of adipose tissue present in the body), more leptin hormone is produced, which leads to decreased ability for the brain to identify the hormone, triggering another cycle of hunger all over again⁷.
With more research being done to better understand the importance that our gut plays in overall health, it turns out that the bacteria living in your stomach and intestinal tract may play a role in your likelihood of gaining weight. Studies have shown that people living with obesity tend to have different types of bacteria living within their gut compared to their peers who can maintain a healthy weight⁸. Possibly caused by the different ways bacteria can break down food and harvest the needed energy for day-to-day activities, more research is needed to fully understand the impact of our gut health on our risk of developing obesity.
Many people living with obesity are also diagnosed with other medical conditions that can require treatment with various medications. Diabetes, anxiety, depression, high blood pressure, and hypothyroidism are all conditions that are associated with a diagnosis of obesity — and while getting the correct treatment for these conditions is important for improved health, it may be leading to increased weight gain at the same time. Medications such as antidiabetics, mood stabilisers, and antidepressants all come with the side effect of weight gain, making losing weight even more difficult.
Junk food addiction is a real, complex issue that impacts many people all around the world. As the number of fast-food locations continues to increase, it seems that we are truly addicted to the taste of highly processed and fried foods. From a greasy cheeseburger to your favourite flavour of salty potato chips, junk food is full of fat, sodium, sugar, and preservatives that make us crave them even after we are full. With nearly 45% of American adults consuming some sort of fast food on any given day, it appears that the convenient and addictive nature of these foods is having a larger impact on our dietary choices than we may realize⁹.
Even when we make conscious efforts to avoid fast food, lots of the food we have available to use at local grocery stores are full of hidden added sugar and preservatives. Contributing many unnecessary calories to seemingly healthy choices, added sugars can be found in almost all processed goods. With some of the worst offenders for added sugar including soft drinks, baked goods, fruit juices, and breakfast cereals, it can be tough to avoid the unnecessary calories unless you are educated about how to properly read food labels and are making a conscious effort to buy healthy alternatives¹⁰.
Depending on where you grew up, you may not have had access to regular healthy foods. Whether you grew up in a developing country that regularly experienced food shortages or lived in a rural setting far away from a local grocery store or farmer market, there are many different reasons why people may struggle to eat fresh and healthy meals.
In addition to healthy food scarcity, the price of healthy food is often a barrier that prevents people from choosing healthier options when they go grocery shopping. While produce like fresh fruit and vegetables offers excellent nutritional benefits, they are often more expensive and quick to perish when compared to processed snacks that contain high amounts of sugars and preservatives. This limited access and cost disparity can significantly contribute to a person’s ability to maintain a healthy weight throughout their lifetime.
With over 20% of children aged five through nine already meeting the criteria for being overweight, it is apparent that we need to improve the amount of nutritional information that is taught to both children and their parents around the world¹¹.
With a seemingly endless stream of junk food advertisements (many of which are aimed at children), it can be challenging to determine which foods are a healthy choice and which are not. As the obesity epidemic continues to grow from year to year, it is apparent that increased education about how to create a balanced diet is needed more than ever.
With a multitude of factors causing obesity, increased education about the disease is essential in creating sustainable and actionable plans that decrease its burden and impact around the world. Looking to find ways to promote improved access to nutritional food and education, the CDC has created a list of state and community actions designed to act as stepping stones to tackling this ever-growing epidemic. Some of the recommendations include¹²:
Increasing the selection of healthier foods from food vendors — Looking to add more healthy choices for consumers, this initiative aims to encourage popular food vendors to offer healthier options, increase the number of healthy foods in food pantries, and improve nutritional guidelines in any new food-related contracts.
Connected people to healthier foods — This goal is designed to provide better access to healthy foods by addressing food gaps. By supporting improved food transportations systems and developing more robust farm-to-market processes, people will be better able to connect to healthy food choices.
Creating partnerships with healthy food providers — Aiming to help provide healthier choices by improving the affordability of healthy ingredients, linking local food providers to food organisations, this goal hopes to overcome many of the common barriers of purchasing healthy food on an industry and individual level.
These initiatives, paired with increased efforts to decrease the societal stigma against people living with obesity, are a great starting point for reducing the number of people living with this disease. Over time, the CDC hopes to provide a broader range of nutritional resources to promote more balanced eating habits worldwide.
Prevalence of obesity among adults, BMI ≥ 30, crude estimates by WHO region | World Health Organization
Obesity | World Health Organization
Genes are not destiny: obesity-promoting genes in an obesity-promoting world | Harvard School of Health
Obesity Our World in Data
Obesity and hormones | Better Health
Leptin and leptin resistance: what you need to know | Healthline
Fast food consumption among adults in the united states, 2013–2016 | Center for Disease Control and Prevention
How much sugar do you eat? You may be surprised! | United States Department of Health and Human Services
Healthy food environments: Improving access to healthier food | Center for Disease Control and Prevention
The author, Claire Bonneau, is a medical writer and certified trauma operating room nurse.
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