Since this ratio is not usually given on the package label, you can check the label for grams of saturated fat. The lower the better. Adding oils to the diet has become almost an obsession for some people. However, large quantities of unsaturated fat are not recommended. Using large amounts of any fat can contribute excess calories which can lead to obesity.
Obesity is another risk factor for heart disease.
On an 1800 calorie diet this is equal to the amount of fat in three tablespoons of oil. The relation between fat and cancer is not as conclusive as the relation between fat and heart disease. However, there is some evidence that low fat diets may help prevent cancer of the breast, colon and prostate. We don't know if fat is the problem or if excess calories is the problem, but decreasing fat in the diet will also decrease calories. The amount of fat we need per day is usually expressed as a percent of total calories.