A Balb/c mice model to evaluate the impact of excess lipid on cancer development. Immediately after tumour implantation, mice were separated into two groups. One group was fed a lean diet (Harlan Teklad, Indianapolis, IN, Cat. No. 7001) with 4.25% fat and 3.82 Kcal/g, and the other group was fed high fat diet (Research Diets, New Brunswick, New Jersey, Cat. No. D12492) with 34.9% fat and 5.24 Kcal/g. Intravital flow cytometry and histology analysis were employed to enumerate circulating tumour cells (CTCs) in bloodstream and metastasized colonies in lung tissues, respectively. Additionally, primary tumour size, animal weight, weight of visceral adipose tissues, and concentration of plasma FFAs were also measured.