With all the emphasis on the health risks of obesity, you may think a few extra pounds are harmless, but new research shows otherwise. A study found that many overweight, but not quite obese, people are dealing with health problems related to their extra body weight, including some that are potentially fatal.

More than 2 billion children and adults suffer from health problems related to their weight, the study found. What’s more, of the 4 million deaths associated with excess body weight in 2015, about 40 percent occurred in individuals who were overweight, but not heavy enough to be considered obese. These deaths were attributed to illnesses such as cardiovascular disease and diabetes. Illnesses associated with higher body mass indexes (BMIs) include cancers of the esophagus, colon and rectum, liver, gallbladder and biliary tract, pancreas, breast, uterus, ovary, kidney, thyroid, and leukemia.

Read: Obesity In America: More Women Than Men Are Now Overweight, In Need Of Better Prevention Methods

"People who shrug off weight gain do so at their own risk — risk of cardiovascular disease, diabetes, cancer, and other life-threatening conditions," said study author Dr. Christopher Murray in a recent statement. "Those half-serious New Year's resolutions to lose weight should become year-round commitments to lose weight and prevent future weight gain."

The study is based on information from 196 countries and spanned from 1980 to 2015. In addition, the study revealed that the number of overweight adults and children has been steadily growing since 1980. As defined by the study, obesity is characterized by having a BMI of 30 or higher, and overweight is characterized by having a BMI between 25 and 30.

While Americans may get the most criticism for their expanding waistlines, weight gain is a global issue, although it has affected countries differently. For example, according to the press release, the highest level of obesity among children and young adults can be found in the U.S., with 13 percent of this demographic considered obese. The country with the highest percentage of obese adults was Egypt, with 35 percent of the adult population clinically obese. As for numbers though, China and India had the highest numbers of obese children, at 15 and 14 million respectively, and the U.S. and China had the highest numbers of obese adults, at 79 and 57 million, respectively.

"Excess body weight is one of the most challenging public health problems of our time, affecting nearly one in every three people," said the study’s lead author, Dr. Ashkan Afshin, in a statement.

The reason for these increases in obese and overweight adults and children is hard to pin down to one factor. For example, according to Bloomberg, raising incomes, changing food supplies, and declines in physical activity are all likely to play a role. For the first time in human history, many populations have a surplus of food rather than a deficit. As a result, we tend to eat too much of it as humans are evolutionarily designed to stock up on energy. However, more energy intake and less opportunity to burn it off results in excess weight, in some cases a deadly amount of excess weight.

Source: Afshin A, et al. Health Effects of Overweight and Obesity in 195 Countries over 25 Years. The New England Journal of Medicine . 2017

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