The link between fat and cancer is now undeniable. Many breast tumors are "fueled" by estrogens, the female sex hormones for women and men. The more estrogen there is, the greater the driving force behind breast cancer. The principal estrogen is estradiol, and the amount of estradiol produced by the body is linked to the amount of fat and fibre in the diet. High-fat diets increase estradiol production and low-fat diets decrease it. Consumption of high-fat foods such as meat, dairy and fried foods cause a woman’s body to make more estrogen, which encourages cancer cell growth in the breast and other organs that are sensitive to female sex hormones. Estradiol is carried in the blood on special carrier molecules. On high-fat diets, estradiol breaks free from its carrier molecules and becomes biologically active, like soldiers jumping off a jeep and starting their attack.

Meat, poultry, fish, and dairy products that make up a high fat diet have no fibre. Fibre reduces estrogen levels in the body by trapping it in the digestive tract and moving it out of the body. Without fibre, the estrogen is reabsorbed from the intestine into the bloodstream increasing cancer risk.

One study noted a 200 % increase in breast cancer among those who consume beef or pork five to six times per week. When the amount of fat in the diet is reduced and vegetables, fruit and grain are increased , the estrogen levels are held at a lower and safer level. A 2003 study in the Journal of the National Cancer Institute found that when girls ages eight to ten reduced the amount of animal fat in their diet and added vegetables, fruit and grains , the amount of estradiol in their blood dropped by 30 percent. Similarly, a group of women switched from a high-fat, low-fibre diet (40% of calories as fat and 12 g/day of fibre) to a low-fat, high-fibre diet (20% of calories from fat and 40 g/day of fibre). Within two months their estrogen level had dropped by 46%.