Gastric cancer remains one of the most common and deadly cancers globally, particularly among older males. According to GLOBOCAN 2018 data, it is the fifth most common neoplasm and the third most deadly cancer, with an estimated 783,000 deaths in 2018. Incidence and mortality rates vary significantly by region and are highly dependent on diet and *Helicobacter pylori* (H. pylori) infection. While efforts to prevent and treat H. pylori have reduced overall gastric cancer incidence, they have also led to an increase in cardia gastric cancer, a rare subtype that has increased sevenfold in the past decades. The etiology of gastric cancer is complex, with both genetic and environmental factors playing significant roles. Genetic variants such as GSTM1-null phenotype, CDH1 gene mutations, and Lynch syndrome contribute to 1–3% of cases. Environmental factors include diet, smoking, alcohol consumption, occupational exposure to harmful substances, and obesity. Diet, in particular, is a major modifiable risk factor, with a diet rich in fruits and vegetables being protective, while high-salt, pickled, and processed foods increase the risk. Prevention strategies focus on lifestyle modifications, including dietary changes, smoking cessation, and exercise. Genetic testing is also enabling earlier diagnosis and better survival rates. Despite global strides in prevention and treatment, gastric cancer remains a significant health concern, with ongoing research aimed at understanding the disease's etiology and developing more effective prevention and treatment strategies.Gastric cancer remains one of the most common and deadly cancers globally, particularly among older males. According to GLOBOCAN 2018 data, it is the fifth most common neoplasm and the third most deadly cancer, with an estimated 783,000 deaths in 2018. Incidence and mortality rates vary significantly by region and are highly dependent on diet and *Helicobacter pylori* (H. pylori) infection. While efforts to prevent and treat H. pylori have reduced overall gastric cancer incidence, they have also led to an increase in cardia gastric cancer, a rare subtype that has increased sevenfold in the past decades. The etiology of gastric cancer is complex, with both genetic and environmental factors playing significant roles. Genetic variants such as GSTM1-null phenotype, CDH1 gene mutations, and Lynch syndrome contribute to 1–3% of cases. Environmental factors include diet, smoking, alcohol consumption, occupational exposure to harmful substances, and obesity. Diet, in particular, is a major modifiable risk factor, with a diet rich in fruits and vegetables being protective, while high-salt, pickled, and processed foods increase the risk. Prevention strategies focus on lifestyle modifications, including dietary changes, smoking cessation, and exercise. Genetic testing is also enabling earlier diagnosis and better survival rates. Despite global strides in prevention and treatment, gastric cancer remains a significant health concern, with ongoing research aimed at understanding the disease's etiology and developing more effective prevention and treatment strategies.