It may not necessarily be a bad thing, however research has shown that obese individuals have a lower average life expectancy of approximately 9 years for an adult female and 12 years for an adult male, than their normal weight counterparts. This is largely due to the effect of obesity on the body, which can affect anywhere from the head to the toes. Some of the common obesity-related illnesses are Type 2 diabetes, hypertension and sleep apnea. Of course there can also be quality of life issues such as lack of mobility, low self-esteem and decreased social interaction which some obese individuals suffer from.