You know when you have the impression of reading everything and the opposite of everything about nutrition?

Have you ever read that a major scientific study has established that milk is bad, that carbohydrates are bad or that a particular diet gives more results than a traditional diet for weight loss?

Well, in the last fifteen years we have seen a real boom in nutrition studies on the benefits of certain foods, on the link between other foods and diseases and on even drastic weight loss methods.

And although Dcomedieta always tries to talk about objective nutrition studies, I guarantee you that it is not easy to extricate yourself every day from the alarming news about this or that food.

NUTRITION STUDIES: THE MAIN LIMITS YOU NEED TO KNOW

• Big problems can be found in epidemiological studies, those that link certain foods to disease or obesity. A correlation between one data and another does not create a cause-and-effect relationship.
  Because thousands of variables are not taken into account.
• In the majority of these studies, the subjects analyzed often have to fill out questionnaires on a monthly, semiannual, yearly or even once every two years to tell what they ate.
  Now: which of you remembers what you ate last week?
• At the same time, in the past I had already denounced the serious limitations of some studies that had jumped to the honors of the press. A famous study on the benefits of the Mediterranean diet from 2013 has meanwhile been withdrawn , because the data collected by the scientists were inaccurate and manipulated.When I wrote this article I stressed the fact that as many as 700 nutrition studies a year followed the same fate. But in the meantime, these studies have been published, commented on and influenced people’s nutrition.

• Some researchers have been sued.

  But this public opinion does not know, at least in Italy.
  The most famous case was that of Brian Wansick, accused of having manipulated 13 studies that linked nutrition to behavioral psychology , he published another 15 studies that have been reworked and corrected by other researchers.

• There have been big turnarounds on meat , on fructose , on the glycemic index, on obesity.  
• Recently, it is back to “clear” the eggs.
  New limits were found on epidemiological studies linking eggs to high cholesterol. 

As doctors Ludwig and Heymsfield point out in the New York Times (my translation).

We continue to lack effective dietary prevention, in part because clinical trials have been too poorly conducted and fine-tuned to draw firm conclusions. We are still debating issues that have been going on for decades: Should we focus on reducing carbohydrates or fat? Is sugar toxic? What should we think of sweetened drinks or alcohol in minimal quantities?

And what looked like a big, fat, suspicious one, has now become public knowledge thanks to these investigations