The causes of obesity are numerous and diverse. Rather than simply listing them, let’s explore them based on which ones you can control and which you can’t…
When obesity causes can be impacted by your daily decisions and actions, they can be said to be under your “direct control.” In other words, direct causes of obesity are typically the result of your chosen lifestyle.
Many “experts” often attempt to cram the direct obesity factors into one neat and tidy formula:
From this viewpoint, in order to lose weight all you need to do is exercise (burn) off more calories than you eat. But things are a little more complicated than that…
A sedentary lifestyle means living with minimal (or zero) physical activity. The dangers of a sedentary lifestyle include developing obesity and other health problems (1). Unfortunately, this dangerous lifestyle is becoming more common as obesity rates rise (2).
Trends toward a sedentary lifestyle and obesity appear to be starting at a young age childhood Engagement in physical activity is decreasing, contributing to the rising obesity rates (3). Additionally, the amount of time children spend watching television is proportional to the risk of developing obesity (4).
In adults, various factors contribute to the rise in sedentary lifestyles. These include ease of transportation, jobs without physical activity, and technology (5).
Another factor that can lead to obesity is poor sleep hygiene (6). A lack of sleep stresses the body, disrupts hormone regulation, and interferes with sugar processing. As a result, obesity risk is increased for people who sleep less than six hours a night (7).
Food addiction is compulsive eating despite negative consequences. Dopamine plays a significant role in addiction, and studies have confirmed a relationship between dopamine and food (8). Most unhealthy, desirable foods (think pizza and candy) release more dopamine in our brains than healthy foods (think vegetables and beans) (9).
Screening for food addiction is sometimes the first step in obesity treatment. If food addiction is present, there may be additional treatment recommendations that includes psychotherapy . Psychotherapy will address emotional issues that contribute to compulsive eating.
For more information, see our page Food Addiction Treatment: Symptoms, Diagnosis, & Potential “Cures”
From the diet, or “calories consumed”, standpoint, the confluence of 3 factors can lead to obesity:
According to Merriam-Webster, a calorie is the amount of heat (energy) required to raise the temperature of one gram of water one degree Celsius. But this definition does not go far enough.
Using the results from numerous satiety studies, NutritionData created a complex formula that determines the “Fullness Factor” (the higher the rating, the fuller you feel per calorie consumed) of a variety of common foods based on their nutritional content:
If a calorie were a calorie regardless of its source, we could just load up on ice cream and french fries every meal as long as we exercised enough to burn them off. Common sense tells us this is ridiculous, but why?
In short, all calories are not created equal. Both your body and mind respond to different foods in different ways (10)…
Making up about 60% of your body’s weight, water is the most important substance you consume. So how much do you need to drink?
According to the Institute of Medicine, men should consume just over 15 1/2 cups (3.7 liters) of total beverages per day while women should consume about 11 1/2 cups (2.7 liters).
According to the Economic Research Service (ERS) (14), for the first time since tracking the data, Americans spent more money on food outside the home than they did on food at home.
This is important for two reasons:
If you’re looking for some healthy eating tips, especially if you have already had weight loss surgery, check out our Bariatric Diet page.
Research has proven that we tend to eat all of the food that is placed in front of us, regardless of whether we feel full (17). To control your calories consumed, you must control your portion sizes when eating at home and in restaurants.
For a great read that further explores what you should eat and why, pick up the book In Defense of Food: An Eater’s Manifesto by Michael Pollan.
It will change the way you think about food and, hopefully, the decisions you make when buying it.
Our Fast Food Obesity page provides additional analysis of how food content and portion sizes can lead to obesity, but there’s another more snacky…um…sneaky cause of obesity lurking around every corner…
How many meals do you eat per day? Breakfast, lunch and dinner make three, right?
Not so fast.
When snacking between meals is factored in, the average adult eats the equivalent of four meals per day while the average child eats almost five (18).
The amount of carbohydrates and fats in the average American diet has increased dramatically over the last 40 years, and food and beverage snacks account for almost all of it; Americans today get almost a quarter of all calories from snacking (19).
That takes care of the “calories consumed” part of the weight loss/weight gain formula. Now let’s explore the causes of obesity related to calories burned…
According to the Centers for Disease Control and Prevention, most adults need at least 30 minutes of moderate physical activity at least five days per week. Moderate physical activity includes anything that increases your breathing or heart rate such as walking briskly, bicycling, dancing, swimming or mowing the lawn.
According to recent research of data spanning more than 50 years, another big cause of our rising obesity rates is the drastic reduction of physically-demanding jobs. In 1960, 50% of all jobs in the U.S. required "moderate physical activity. That percentage has now dropped to about 20%.
Currently, over two-thirds of Americans are not achieving this (20).
In addition to burning calories directly, exercise further prevents obesity by increasing metabolism (the rate at which your body burns calories). Just as importantly, exercise reduces abdominal obesity, which is a big predictor of obesity health problems.
Recent research suggests that your metabolic rate may not be as important as previously thought, especially when compared to an improved diet.
Regardless, good weight loss results and better overall health speak for themselves… a healthy diet combined with an appropriate exercise program equals long-term success.
When addressing the causes of obesity, many weight loss professionals, web sites and publications primarily focus on calories consumed versus calories burned. As we’ve discussed, these are certainly big contributors, but there is more to the problem…
Consider the following:
Why do so many people believe that diets high in fat are bad? How has sugar stayed “off of the radar” for so long as a potential cause of obesity?
According to a peer-reviewed publication in the Journal of the American Medical Association, “together with other recent analyses of sugar industry documents, our findings suggest the industry sponsored a research program in the 1960s and 1970s that successfully cast doubt about the hazards of sucrose while promoting fat as the dietary culprit in coronary heart disease (CHD). Policymaking committees should consider giving less weight to food industry–funded studies and include mechanistic and animal studies as well as studies appraising the effect of added sugars on multiple CHD biomarkers and disease development (24).”
In other words, the sugar lobby may have had an impact on the government’s representation of sugar as part of the problem.
As a result of the mounting evidence against sugar, as of 2018, the FDA requires all labels to include the amount of added sugar in each product and it’s percent daily value (labels prior to 2018 were not required to include either of these.
While a healthy diet and adequate exercise may be difficult to achieve due to our stressful and time-strained lifestyles, they remain under our day-to-day control nonetheless.
Two additional causes of obesity are also under our control, but impacting them requires much more work and dedication…
Combined with environmental influences (i.e. diet and exercise), your genes are up to 70% responsible for your body’s weight.
Not only do your genes determine how hungry you feel and your metabolism, but they are also responsible for how heavy your body “wants” to be (also called the Set Point Theory).
But how can your genetics be under your control, even indirectly?
While you cannot change your actual genes, there are a couple of ways that you may be able to work around them.
First, talk with your doctor about whether medication could be an option. If it is, the most effective diet pill for you will most likely fall into one of two categories:
Weight loss surgery is another effective way to alter your body processes, thereby circumventing any obesity predisposition from your genes. However, there are very specific requirements in order to qualify. If you do qualify, surgery is a life-changing decision that should be taken very seriously and carefully considered.
The government recognizes that they can impact the causes of obesity, but critics of government intervention point out the dangers in attempting to usher people towards a healthier lifestyle.
“Obesity laws” that have been considered to date include…
Success in implementing laws like these has been extremely limited, and where success has been achieved, it has rarely gone as far as intended.
For example, junk food has been banned from public school breakfasts and lunches, but little has been done to curb the junk food that is easily available outside of these “official” meals. In addition to junk food and soft drinks filling most on-campus vending machines, many schools have branded fast food available on campus (11.7% of elementary schools, 19% of middle schools and 23.5% of high schools (25).
For those schools without on-campus fast food, chances are there are many options very nearby… fast food companies make a point of it. And children that have a fast food restaurant within 0.10 miles of their school have a 5.2% greater chance of being obese.
Here is what Ray Kroc, founder of McDonald’s Corporation, had to say about opening restaurants close to schools (26)…
“Back in the day when we first got a company airplane, we used to spot good locations for McDonalds stores by flying over a community and looking for schools. Now we use a helicopter, and its ideal.”
Ray Kroc, McDonalds Corp. Founder
Despite the apparent necessity of government involvement in areas like junk food at and around schools, other areas are not so clear-cut. For instance, a big reason that fast food is so popular is its low cost. It gives low-income individuals, people who may otherwise not be able to afford to feed their families, an inexpensive option to eat. While government taxation on fast food may encourage the purchase of healthier alternatives for those who can afford it, it may make three meals per day unaffordable for low-income families.
From a less humanistic point of view, critics of government intervention point out that obesity taxes unfairly impose on your freedom of choice. In other words, if you want a burger, what gives the government the right to make you pay more for it while they pocket the difference?
Critics also site the fundamentals of capitalism and the importance of allowing the free market to decide what it wants. After all, the increase in popularity of organic products, even with their higher cost, shows that the market is capable of making healthy decisions.
But proponents of obesity legislation draw upon the cigarette tax analogy: just like cigarettes, obesity results in a much larger overarching public health concern that negatively affects the lives of everyone (i.e. increasing healthcare costs) and should therefore be addressed with public policy.
It has also been suggested that government involvement can take us in the opposite direction. For example, the creators of the documentary Food, Inc. suggest that government food industry subsidies make unhealthy food cheaper, thereby encouraging more of the population to consume unhealthy food.
Another example is the government-published Choose My Plate Initiative.
At a minimum, the Choose My Plate Initiative is far too general. At a maximum, the recommendations of the Choose My Plate Initiative significantly contribute to public misperceptions about what to eat.
For instance, as explored further up the page, all calories from carbohydrates are not created equal and should not be lumped together into one group. In addition to its problem with generalization of food groups, nuts are not featured despite their positive health effects.
Critics of the Choose My Plate Initiative also question the organization who is responsible for it: the United States Department of Agriculture (USDA). The USDA is responsible for promoting and regulating agriculture, not for overseeing the health of America. These critics feel that agencies directly responsible for health issues such as the National Institutes of Health (NIH) or the Department of Health and Human Services are much more qualified to create unbiased recommendations.
Government’s recognition of their potential impact on the causes of obesity continues to increase, and a good supporting argument for it exists in at least some areas. The difficulty comes with walking the tight rope between encouraging positive behavior change and hindering individual freedom of choice. Regardless of the level of government involvement, care must be taken and changes must be made in order to keep the fight against obesity moving in the right direction.
Other factors indirectly under your control are the relative nutritional value of your food and its availability.
First, food just isn’t as healthy as it used to be. For example, from 1977 to 2010 there was a 30% increase in the amount of added sugars in foods that Americans eat.
In terms of calories, Americans went from eating 277 calories worth of sugar per day to 329 calories of sugar per day. The problem with having more sugar in foods is that it’s energy-dense and nutrient-poor. In other words, we’re trading healthy calories for unhealthy ones.
The other problem is the availability of healthy food. A study published in 2010 in the American Journal of Preventive Medicine found that the available amount of “dark-green/orange vegetables and legumes and whole grains were entirely insufficient relative to recommendations, with virtually no change over time” (27). In other words, there’s not enough healthy food to go around.
Unfortunately, some factors of obesity are just out of your control. Here are some examples:
Advertising can have a big impact on our behaviors, which is why food companies spend so much money on advertising. This would be fine if they were advertising healthy food, but unfortunately, this advertising goes in large part to unhealthy food.
Also, that spending is going up – from 2010 to 2014, a study by the Rudd Center for Food Policy and Obesity found a large spending increase in ads targeting children and teens. For example, they found:
In addition to TV advertising, there is a significant amount of internet advertising directed at older children and teens. From 2010 to 2014 snack food companies placed 163 million ads on Facebook and Youtube, a month. This content also often gets shared by teens, amplifying the reach of these ads.
The obesity virus increases the amount that your fat cells can hold and speeds up the rate at which they mature. Although it can be “caught” from other people, not everyone who has it is obese or even overweight. One study found that about 30% of obese people and 11% of lean people have the virus in their system.
Research has also shown that some obese people carry different types of intestinal bacteria than lean people (28). According to Dr. Andrew Gewirtz, PhD of Emory University, “intestinal bacteria contribute to changes in appetite and metabolism.”
The current scientific consensus is that the bacteria each of us has in our intestines was inherited from our parents. However, Dr. Gewirtz’s research found that intestinal bacteria causing increased appetite in mice can be transferred from mouse to mouse, suggesting the same may hold true for humans. His team is planning future research in humans to determine whether this is the case.
Unfortunately, if you have the obesity virus or hunger-inducing intestinal bacteria, there is currently no treatment to get rid of them. Also, with so many screens in today’s world, it’s almost impossible to avoid advertising of some kind. The good news is that even if you are affected by them, they play only a small role in your overall weight when compared to the causes of obesity that are under your control.
As we’ve discussed, there are several causes of obesity, most of which are either directly or indirectly under your control. Depending on your situation, consider adopting one or more of the following approaches…
[ Last editorial review/modification of this page : 01/11/2018]