It is weak-ass guestimation often tarred by motivated research objectives

From Nutrition Science Is Broken. This New Egg Study Shows Why. by Timothy F. Kirn.

It's been a tortuous path for the humble egg. For much of our history, it was a staple of the American breakfast — as in, bacon and eggs. Then, starting in the late 1970s and early 1980s, it began to be disparaged as a dangerous source of artery-clogging cholesterol, a probable culprit behind Americans’ exceptionally high rates of heart attack and stroke. Then, in the past few years, the chicken egg was redeemed and once again touted as an excellent source of protein, unique antioxidants like lutein and zeaxanthin, and many vitamins and minerals, including riboflavin and selenium, all in a fairly low-calorie package.

This March, a study published in JAMA put the egg back on the hot seat. It found that the amount of cholesterol in a bit less than two large eggs a day was associated with an increase in a person’s risk of cardiovascular disease and death by 17 percent and 18 percent, respectively. The risks grow with every additional half egg. It was a really large study, too — with nearly 30,000 participants — which suggests it should be fairly reliable.

So which is it? Is the egg good or bad? And, while we are on the subject, when so much of what we are told about diet, health, and weight loss is inconsistent and contradictory, can we believe any of it?

Quite frankly, probably not. Nutrition research tends to be unreliable because nearly all of it is based on observational studies, which are imprecise, have no controls, and don’t follow an experimental method. As nutrition-research critics Edward Archer and Carl Lavie have put it, “’Nutrition’ is now a degenerating research paradigm in which scientifically illiterate methods, meaningless data, and consensus-driven censorship dominate the empirical landscape.”

Other nutrition research critics, such as John Ioannidis of Stanford University, have been similarly scathing in their commentary. They point out that observational nutrition studies are essentially just surveys: Researchers ask a group of study participants — a cohort — what they eat and how often, then they track the cohort over time to see what, if any, health conditions the study participants develop.

The trouble with the approach is that no one really remembers what they ate. You might remember today’s breakfast in some detail. But, breakfast three days ago, in precise amounts? Even the unadventurous creature of habit would probably get it wrong. That tends to make these surveys inaccurate, especially when researchers try to drill down to specific foods.

Then, that initial inaccuracy is compounded when scientists use those guesses about eating habits to calculate the precise amounts of specific proteins and nutrients that a person consumed. The errors add up, and they can lead to seriously dubious conclusions.

Indeed.

Much of public discussion is informed by junk science of exactly this sort. It looks like science, it smacks of science, it is said to be science, but it is weak-ass guestimation often tarred by motivated research objectives.

Yet anyone questioning the received wisdom of these travesties of science is then assailed as a science denier. We need to clean up our discourse, not just making it more civil but also returning to the hard facts of science and the humility to know that there are many important things that stubbornly remain beyond our knowledge frontier.

AGW, suicide, economic forecasting, much of psychology and sociology, political science, all political polling, drug policy, etc. are dominated by cognitive pollution of the worst sort. We want to fix real problems but the fact that real knowledge is hard to find, expensive to generate, nuanced and particular drives us to the fake satisfaction of observational studies.

Related: The Fundamental Problem with Most Nutrition Research by Chris Kresser and Observational nutritional studies: garbage in, garbage out by Neo.