Does a Low Fat Diet Improve Your Health? - Colorectal Cancer and Heart Disease

In general the results from the WHI study on colorectal cancer are similar to those in the breast cancer study. The low fat eating pattern was associated with a Risk Ratio of 1.08 (Margin of Error between 0.90 and 1.29). This lack of significant effect applies to total cancer incidence, total cancer mortality and total mortality.

Another branch of this study examined the impact of a low fat diet on Coronary Heart Disease (CHD), fatal and nonfatal stroke, and CVD (CHD and stroke together). LDL cholesterol (the "bad" cholesterol) was slightly lower in the group with low fat consumption, HDL cholesterol (the "good" cholesterol) was not impacted, and the blood pressure was not significantly changed. The Risk ratio for CHD was 0.97 (Margin of Error between 0.90 and 1.06), for stroke - 1.02 (Margin of Error between 0.90 and 1.15), and for CVD - 0.98, (0.92 to 1.05). In other words, clearly a low fat diet that reduces normal fat intake by about one third, does not help women in the 50-79 age group.

Other interesting "factoids" are buried in one of the tables of reference 3: women with a waist circumference above 98 cm (39 inches) have more than double the risk for CHD compared to women with a waist circumference below 79 cm (31 inches). This is not unexpected, and we have already covered it in our obesity series. We also learn from this study that increasing carbohydrate consumption (to compensate for the reduced consumption of fats) did not result in any adverse effects on lipid profiles (various types of cholesterol levels), or levels of glucose or insulin. Smokers (during the course of the study) had more than double the risk for CHD compared to women who had never smoked, or who had stopped smoking before the start of the study.