Why Obesity Isn’t a Choice: The Causes

Why Obesity Isn’t a Choice: The Causes

Society has come a long way when it comes to body positivity - overweight people aren’t the butt of every joke anymore, but that doesn’t mean there isn’t a stigma. Many people believe that obesity is a choice - blaming the person’s poor dietary and lifestyle choices.

Obesity is now understood to be a disease, not a decision. Genetics, upbringing, socioeconomic status, education, poor gut health, and medical conditions can all impact a person’s weight. Simply put, obesity is not a choice.

So what can cause obesity?



Family history correlates with many diseases including obesity. There are at least 125 different genes that result in obesity, np matter what environment. Additionally, what’s fascinating is that a mother’s diet can affect how her child will behave and eat later in life. One study found that the children of mothers who gain excess weight during pregnancy are likely to be overweight by just three years old. Children with overweight parents and grandparents are also notably more likely to become obese than children with parents and grandparents who are average weight.

Medications and medical conditions

Some medications have side effects that cause weight gain including diabetic medications, beta-blockers, ADHD medications, and certain antidepressants. Some conditions such as polycystic ovary syndrome (PCOS), heart failure, and hypothyroidism can also cause weight gain.

While some of these medications are said to cause inadvertent weight gain, it’s also worth noting that some of the issues mentioned (such as depression, ADHD, and PCOS) may have psychological effects that can cause patients to overeat and gain weight.


Hunger hormones in particular are very powerful at influencing the brain's craving and reward center. In people with obesity, these hormones are imbalanced, driving the secretion of the hormone ghrelin, which increases the appetite. In certain individuals, junk food consumption increases the release of endorphins when compared to whole foods, sending a more powerful “reward” signal from the brain. In other words, a habit of overeating doesn’t always come from a lack of self-restraint or greediness.

Poor gut health

The gut microbiome has been studied significantly and shown to be key to overall health. Those with obesity tend to have different flora than others, which can affect metabolism rates. Furthermore, the gut bacteria in obese people may be more efficient at taking energy from food, which can increase the daily caloric needs.

Unfortunately, the gut bacteria of those who are obese make it easier for them to store fat, continuing the cycle of weight gain. Once a person reaches a certain size, it’s even harder to exercise regularly and lose weight, so the cycle continues.

Weight Loss is Possible


While multiple factors increase the risk of obesity, there are also ways to help the root cause of obesity. The stigma of weight loss drugs as a crutch should be seen as a correction of the biological causes rather than an easy way out. GLP-1 medications (medication originally given to patients with type 2 diabetes but which can also cause weight loss) are one class of meds that fix the root problem.

While many people are overweight as a result of overeating and not exercising, there are several factors to remember when ascertaining someone’s reasons for being obese. If you’re worried about your weight, don’t take these reasons as a sign you’re doomed! A lifestyle change can get you on the road back to health and, with the help of a doctor, other options such as GLP-1 medications can help you overcome many of these barriers. Ready to start your weight loss journey? Learn more here.


Dr. Nancy Rahnama, MD, ABOM, ABIM, is a medical doctor board certified by both the American Board of Obesity Medicine and the American Board of Internal Medicine. Her specialty is Clinical Nutrition, that is, the use of nutrition by a medical doctor to diagnose and treat disease. Dr. Rahnama has helped thousands of people achieve their goals of weight loss, gut health, improved mood and sleep, and managing chronic disease.