Explain the relationships among dietary fats, cancer, and obesity.

Question

What will be an ideal response?

Answer 1

The links between dietary fats and cancer are not as evident as they are for heart disease. Dietary fat does not seem to initiate cancer development, but instead may promote cancer once it has arisen. Stronger risk factors for cancer include smoking, alcohol, and environmental contaminants.
The relationship between dietary fat and the risk of cancer differs for various types of cancers. In the case of breast cancer, evidence has been weak and inconclusive. Some studies indicate an association between dietary fat and breast cancer; more convincing evidence indicates that body fatness contributes to the risk. In the case of colon cancer, limited evidence suggests a harmful association with foods containing animal fats.
The relationship between dietary fat and the risk of cancer differs for various types and combinations of fats as well. The increased risk in cancer from fat appears to be due primarily to saturated fats or dietary fat from meats (which is mostly saturated). Fat from milk or fish has not been implicated in cancer risk. Olive oil seems to have a protective effect.
As to obesity, fat contributes more than twice as many kcalories per gram as either carbohydrate or protein. Consequently, people who eat high-fat diets regularly may exceed their energy needs and gain weight, especially if they are inactive. Because fat boosts energy intake, cutting fat from the diet can be an effective strategy in cutting kcalories. In some cases, though, choosing a fat-free food offers no kcalorie savings. Fat-free frozen desserts, for example, often have so much sugar added that the kcalorie count can be as high as in the regular-fat product. In this case, cutting fat and adding carbohydrate offers no kcalorie savings or weight-loss advantage. In fact, it may even raise energy intake and exacerbate weight problems. Later chapters revisit the role of dietary fat in the development of obesity.