There are many risk factors for overweight and obesity. Some risk factors can be changed, such as unhealthy lifestyle habits and environments.
Other risk factors, such as age, family history and genetics, race and ethnicity, and sex, cannot be changed. Heathy lifestyle changes can decrease your risk for developing overweight and obesity.
Unhealthy lifestyle habits
Lack of physical activity, unhealthy eating patterns, not enough sleep, and high amounts of stress can increase your risk for overweight and obesity.
Lack of physical activity
Lack of physical activity due to high amounts of TV, computer, videogame or other screen usage has been associated with a high body mass index.
Healthy lifestyle changes, such as being physically active and reducing screen time, can help you aim for a healthy weight.
Unhealthy eating behaviors
Some unhealthy eating behaviors can increase your risk for overweight and obesity, including:
Eating more calories than you use. The number of calories you need will vary based on your sex, age, and physical activity level. Find out your daily calorie needs or goals with the Body Weight Planner.
Eating too much saturated and trans fats.
Eating foods high in added sugars.
Visit Heart-healthy eating for more information about healthy eating patterns.
Not enough sleep
Many studies have seen a high BMI in people who do not get enough sleep. Some studies have seen a relationship between sleep and the way our bodies use nutrients for energy and how lack of sleep can affect hormones that control hunger urges.
Visit our Sleep Deprivation and Deficiency Health Topic for more information about lack of sleep.
High amounts of stress
Acute stress and chronic stress affect the brain and trigger the production of hormones, such as cortisol, that control our energy balances and hunger urges.
Acute stress can trigger hormone changes that make you not want to eat. If the stress becomes chronic, hormone changes can make you eat more and store more fat.
Childhood obesity remains a serious problem in the United States, and some populations are more at risk for childhood obesity than others. The risk of unhealthy weight gain increases as you age.
Adults who have a healthy BMI often start to gain weight in young adulthood and continue to gain weight until 60 to 65 years old, when they tend to start losing weight.
Many environmental factors can increase your risk for overweight and obesity:
Social factors such as having a low socioeconomic status or an unhealthy social or unsafe environment in the neighborhood.
Built environment factors such as easy access to unhealthy fast foods, limited access to recreational facilities or parks, and few safe or easy ways to walk in your neighborhood.
Exposure to chemicals known as obesogens that can change hormones and increase fatty tissue in our bodies.
Family history and genetics
Genetic studies have found that overweight and obesity can run in families, so it is possible that our genes or DNA can cause these conditions. Research studies have found that certain DNA elements are associated with obesity.
Eating too much or eating too little during your pregnancy can change your baby’s DNA and can affect how your child stores and uses fat later in life.
Also, studies have shown that obese fathers have DNA changes in their sperm that can be passed on to their children.
Race or ethnicity
Overweight and obesity is highly prevalent in some racial and ethnic minority groups. Rates of obesity in American adults are highest in blacks, followed by Hispanics, then whites.
This is true for men or women. While Asian men and women have the lowest rates of unhealthy BMIs, they may have high amounts of unhealthy fat in the abdomen.
Samoans may be at risk for overweight and obesity because they may carry a DNA variant that is associated with increased BMI but not with common obesity-related complications.
In the United States, obesity is more common in black or Hispanic women than in black or Hispanic men. A person’s sex may also affect the way the body stores fat. For example, women tend to store less unhealthy fat in the abdomen than men do.
Overweight and obesity is also common in women with polycystic ovary syndrome (PCOS). This is an endocrine condition that causes large ovaries and prevents proper ovulation, which can reduce fertility.