Food for thought: Reasons why the "ideal" diet is disputed

The majority of studies on diet are very poorly controlled and when the results don't match up to the expected outcomes the researchers either blame the complexity of the human body or people for lying about what they ate. It's an environment where the only acceptable outcomes are that which we already believe so our knowledge is stagnating. Meanwhile because of all the inconclusive and conflicting studies the experts can essentially pick and choose what they want to believe is true making health sciences more of a health religion.

There exists scientific peer reviewed evidence to suggest that vegan, vegetarian, omnivore, low-carbohydrate, low-fat, and regional diets like the Mediterranean are the best for overall health and longevity. Obviously these diets have a lot of conflicting recommendations, but almost every major issue on health has conflicting and inconclusive evidence to include what causes cardiovascular disease, what raises serum cholesterol, what are the dietary contributions to diabetes, dietary contributions to cancer, and what is causing the obesity epidemic. This handful of topics alone covers the majority of death caused by dietary contributions and the majority of death in first world countries.

It doesn’t take much to identify faults in diet studies and the biggest is self-reported data. Most studies with substantial participant size use self-reported data which has been identified over and over again as error prone. Several of the largest and most influential studies on diet use self-reported data like the Framingham Study, The Nurses’ Study, and NHANES. The results any study produces are only as accurate and reliable as the data gathered by the study. Since self-reported data is both unreliable and inaccurate the results are therefore going to be unreliable and inaccurate.

There are other major faults in many diet studies. For example, in one of the latest studies on the Mediterranean diet there were two significant study design flaws:

1. The control group received only initial counselling then got leaflets yearly for the first three years, while the Mediterranean diet groups got individual and group counseling quarterly.
2. The Mediterranean diet groups were “encouraged to avoid commercially made cookies, cakes and pastries”. Since the control group didn’t have personalized support and weren’t encouraged to avoid these foods how can you distinguish clearly between cutting out these foods and the diet itself?

After three years the researchers woke up and started offering the same counseling to the control group, but after three years of impact from differences in counseling and support the control group is hardly a control group. The study lasted a total of seven years at which point the researchers deemed it “unethical” to continue the study due to emerging mortality differences; however, this can easily be viewed as an excuse to end the study as soon as they got the results they wanted. The researchers in the studies all had major conflicts of interest that would benefit from promoting this type of diet to include major producers of nuts and alcohol.

Although it can clearly be seen the latest Mediterranean diet study is not an unbiased, well controlled study numerous other flaws in study design can be found. If these studies were well controlled and designed then you flat out wouldn’t have the conflicting and inconclusive results we can so easily see.

References:

http://www.nejm.org/doi/full/10.1056/NEJM199212313272701#t=article+Results.

http://www.nejm.org/doi/full/10.1056/NEJMoa1200303