Cause and Effect of Obesity

The cause and effect of obesity may not be as straightforward as you think.

Causes include:

  • How much and what you eat (calories consumed) and how much you exercise (calories burned)
  • Your genetics
  • Government influences
  • Obesity virus and intestinal bacteria

Effects include:

  • A litany of health problems
  • Obesity discrimination

Read and click the sections below to learn more about each of the points above.

Food addiction, lack of exercise, genetics, diet – they all play a role in obesity, but to what extent?

There are 3 categories to consider:

  1. Factors under your direct control like diet, sleep, and exercise
  2. Factors you may be able to control to some degree, such as your genes
  3. Factors completely out of your control, including certain types of intestinal bacteria

See our Causes of Obesity and How You Can Address Them for a breakdown on the science and various factors that contribute to obesity.

Obesity health problems are the second leading cause of preventable deaths and can drastically reduce an obese individual’s quality of life. While a person’s actual weight is certainly a strong predictor of risk, where the weight is distributed throughout the body may be more important.

See our Obesity Health Problems page to learn all of the health risks associated with obesity, whether you are at risk and the three weight loss treatment and prevention options.


Fertility and pregnancy problems are also more likely to plague obese people than those of normal weight (4) (5). Problems range from less severe such as anovulation and a higher risk of headaches and heartburn during pregnancy to much more serious pregnancy-related health problems including gestational diabetes, pre-eclampsia and even intrauterine death.

Babies of obese moms are also more likely to have health troubles such as spina bifida and heart defects.

See our Obese and Pregnant (Pregnancy After Weight Loss Surgery) page for more information.

Weight discrimination is another significant effect of obesity. In addition to leading to emotional problems such as low self esteem and depression, obesity also has a measurable impact on other areas of our lives including work, school and even the doctor’s office.

Our Obesity Discrimination page dives into four of the biggest areas of discrimination against obese people, along with effective ways to deal with each type.

Many of the less obvious effects of obesity slowly and quietly infiltrate our everyday lives. Although they don’t seem to be a big issue on a standalone basis, they can lead to much more serious problems.

For example, one study found an increase in body mass index to be directly correlated with decreased seat belt use in people over 24 years of age (1). Not wearing a seat belt won’t effect the obese person on a day to day basis. But if an accident is had while not wearing one, the risk of serious injury goes up by 50% and the risk of a fatality goes up 60 to 70% (2).

Another study determined that an obese person’s romantic partner was much more likely to become obese (3). Again, as the partner slowly gains weight from week to week, there are no glaring effects outside of the weight gain itself. But as the partner’s weight goes up, they gradually become subject to the same more serious effects of obesity, including health problems, discrimination and fertility and pregnancy issues.



  1. Schlundt DG, et al. BMI and Seatbelt Use. Obesity (2007) 15, 2541–2545; doi: 10.1038/oby.2007.303
  2. Safety Belt Statistics. James Madison University Office of Public Safety. Oct 2004. Available at:
  3. Natalie S. Entry Into Romantic Partnership Is Associated With Obesity. Obesity aop, (2009) | doi:10.1038/oby.2009.97.
  4. The Endocrine Society Press Release: Obesity linked to problems that can cause male infertility. Available at: Obesity-linked-to-problems-that-can-cause-male-infertility.cfm. Accessed: October 6, 2009.
  5. Obesity and infertility. Mandakini Parihar. Reviews in Gynaecological Practice – September 2003 (Vol. 3, Issue 3, Pages 120-126, DOI: 10.1016/ 1471-7697(03 00061-3)