Dukasaur wrote:DoomYoshi wrote:
You can accuse me of rejecting all fad diets a priori. I will accept that accusation and claim that it is the lesser of two evils.
Don't ridicualize it. You said that no nutritional studies are valid without biochemical theory. You're painting with an awful broad brush, not just fad diets.
You want to throw out a VAST body of knowledge about the health benefits of berries for instance,
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068482/ because we don't fully understand all the biochemical pathways involved.
Knowing about the health effects of berries has nothing to do with nutritional studies. It's based on people eating berries for years. It's unscientific knowledge. Nobody has ever advocated not eating berries. However, people publish "eating berries is good for you" as if it is news.
Let's take any particular claim in that study you have presented "demonstrated significant improvements in LDL oxidation". That phrase means something along the lines of "compared to the null hypothesis, people who eat berries have improvement in LDL oxidation". Without going into specifically what their null hypothesis was, let's just assume that it was "compared to people who don't eat berries". That still doesn't actually tell us anything. What if cantaloupe-eaters are the best? Does that mean that it's healthier to eat only cantaloupe instead of berries? No it doesn't, because LDL oxidation is a basic metabolic trait, not directly a result of diet (I really don't want to open the debate about diet and cholesterol, as this has been a giant pissing match for 30 years and I'm not an expert in the field). One problem with nutritional studies is that secondary effects have a more pronounced impact than primary effects*. Greater than any individual item you can eat is the overall diet and metabolism. Perhaps with some supercomputer you could determine the correct number of berries to eat exactly, but I'm not sure how that information helps anyone in any way.
So what are those studies good for? Pretty much nothing. Metabolic pathways are so complete that 99% of what you eat ends up the same no matter what. No matter which animal you eat, it ends up being amino acids. No matter which source of fiber you eat, it ends up being roughage. There are certain chemicals that we can't create and need from our diet, but none of that knowledge came from nutritional studies, it all came from biochemical studies.
I'm not sure the second article you posted is a nutritional study or even accurate. It falls into the same trap that many psychology papers fall into. They aren't describing human psychology but rather the psychology of undergraduates. Undergraduate students care about what it looks like they are eating. Ask a starving man in Africa if he cares about the potato chips that you give him and I bet you will get a different answer. THIS JUST IN: FEMALE UNDERGRADUATES CARE ABOUT IMAGE! SHOCKING DETAILS TONIGHT AT 11!
Trial and Error in a medical sense works very different than trial and error for a nutritional sense. Is anyone suggesting that the best cholesterol drug is to eat more berries?
To put this another way: how can you use this information in your life? What if I find some studies that show things that berries are bad at? How do you decide between the two? Simple, confirmation bias - the cornerstone of nutritional studies.
Maybe if you struggled with cholesterol, you might look up a list of foods that helps you get cholesterol under control. What is more likely is that people look for the best solution(s). Underlying all of this is the possibility that berries may not actually help with cholesterol, without looking at the study, it's impossible to trust it, because it comes out of a murky field of science where doubt is a sensible first defense.
I'm not sure why you have turned an attack on a pseudoscience into a moral crusade. It isn't science, end of story, let's move on with our lives.
*By this I mean that the statistics they use stem from controlled experiments, where all else is equal and the only variable is berries or no berries. This doesn't describe actual studies though, where even controlling for berries is almost impossible (some people eat berries without knowing, some people over- or under-report the amount of berries they eat, not all berries are created equal, some people might think that Swedish Berries count as berries, etc.).
