(NaturalNews) Obesity is defined as a body mass index (BMI) of 30.0 or greater. BMI is a ratio determined by weight and height. With a large percentage of Americans classified as being obese, research is showing the effects extra weight and obesity have on a person's overall health. Recent studies show that obese people have an increased risk of developing common kidney cancer, kidney stones, and an increased risk of having a stroke.

Out of all the participants, 67% of the obese patients had kidney cancer compared to 57% of non-obese patients. Researchers do not know why there is a link between obesity and kidney cancer. Researchers are looking into a secondary link involving diabetes, hypertension, hormonal changes, and decreased immune function.

Researchers at Johns Hopkins University are not clear as to the exact link between obesity and kidney stones. However, they theorize that perhaps people who are obese have different levels of substances in their blood that lead to kidney stones.

These studies provide a closer look at obesity and its impact on health. Although none of the studies conclude a definite cause-effect relationship, the link is definitely there. Obesity has a negative impact on health and people with a BMI of 30 or higher need to take action to reduce their weight to improve their health.