RESUMO
Being overweight or obese is a significant public health problem in the 21st century due to its scale, common existence and its cause-effect association with multiple diseases. Excessive accumulation of adipose tissue in humans is regarded as a major risk factor for development of cardiovascular and skeletal diseases. However, data from recent years have revealed that obesity is also strongly associated with increased risk of the majority of cancers in humans, including those originating from the gastrointestinal tract. During the last few year this association has been thoroughly proven and supported by several epidemiological analyses. The authors present i) the current state of knowledge regarding key (patho)mechanisms that link metabolism of human adipose tissue to development/progression of neoplasms (especially in the gastrointestinal tract), as well as ii) the results of selected clinical studies in which the influence of obesity on risk of gastrointestinal cancer development has been addressed.