Example: How Diet Studies Lie (Whole Grains)
Eat whole grains! They make you healthy and you will live longer!
Who says? People who want to sell them to you, and people who will just say anything and try and prove it with bogus statistics.
We Were Not Meant to Eat This Stuff in the First Place
Mark’s Daily Apple, a website about eating naturally (primal) is about an approach to diets that shows how foods added to the human diet in recent history (measured in thousands of years) are actually less healthy than, for example, “eating like a caveman.” One of the things added to the human diet in recent history has been grains.
Our bodies did not evolve over time by eating cultivated grains. Maybe early humans munched on some when they needed to, but humans were meant to eat lean protein, nuts, and fresh fruits and vegetables, things that were common in our long evolutionary history. Grains were cultivated in the last few thousand years, when people started learning agriculture. This is a tiny blimp in time compared to all of human history.
Just because this cultivation fed more people, it does not prove that it is healthy, or even a good idea. It just shows that it fed more people. There was a practical and economic reason to do it.
In more recent times, we have been hearing all about food groups, and food pyramids, and these always had a bread/grain component. Why? Because there was still a business reason to sell this stuff. A lot of it was crap, and in fact, wheat makes a lot of people sick and they don’t know it. Check this Mayo Clinic link on Celiac Disease.
The latest trend, which even health food suppliers have been fooled by, is to swap “whole grains” for processed grains. This is often backed by all kinds of supposedly scientific studies, with lots of talk about fiber and living better and/or longer. It’s still a bunch of crap.
Mark’s Daily Apple Takes a Skeptical Look at Whole Grain Study
Studies pop up all the time, and they can use numbers in a lot of deceiving ways. One such study was just ripped apart by an entry on Mark’s Daily Apple called “Will Eating Whole Grains Help You Live Longer?” The entry is by Denise Minger, and she found the conclusions to be suspicious.
What Minger doesn’t argue with, is that eating whole grains is better than processed crap. That’s not too hard to argue with. What the study does not prove, and it is just assumed, is if any of this is even good for you or not? One is just less harmful than the other.
Minger points out some problems in this study that are common tricks when one tries to use data to prove a point-they use “confounders.”
What’s a confounder? A quick google finds a definition on wiki-
In statistics, a confounding variable (also confounding factor, lurking variable, a confound, or confounder) is an extraneous variable in a statistical model that correlates (positively or negatively) with both the dependent variable and the independent variable. The methodologies of scientific studies therefore need to control for these factors to avoid a false positive (Type I) error; an erroneous conclusion that the dependent variables are in a causal relationship with the independent variable. Such a relation between two observed variables is termed a spurious relationship. Thus, confounding is a major threat to the validity of inferences made about cause and effect, i.e. internal validity, as the observed effects should be attributed to the independent variable rather than the confounder…
Now my brain hurts. What was that about?
Let’s pick a simpler example. I will just make one up. Suppose you want to sell bathrobes. You do a study that shows that people who spend the most time in bathrobes get less sunburn, and less skin cancer than people who don’t wear them too much. Conclusion: bathrobes are effective in reducing skin cancer. The numbers prove it. Easy.
Of course what you do not say, is that the people who spend the most time in bathrobes are people that stay inside anyway! Duh. They won’t get sunburn or skin cancer as much, because they are inside, in their bathrobes.
This is how food studies lie with confounding statistics. It happens all the time.
More Truth About Grains
Minger’s entry about the study didn’t spend a lot of time on what it really wrong with grains in the first place. She was really showing how bogus the recent news bit was.
For more detail, take a look at “Why Grains Are Unhealthy,” on the same site.
For another view, see “Fiber, Cereals, and Grains; even whole grains and oats are out on a Paleolithic Diet.”
For some balance, South Beach says Whole Grains are OK in Phase 2.
What Does Diet for Humans dot com Really Think?
This site is all about exploring the question of what you should eat, what you should do to be healthy, and who to believe. Overall, I agree with the primal/paleo argument for “eating like a caveman.” Sisson’s primal approach and the Paleo approach are consistent with South Beach Phase 1 (something I had much success with myself) and there is something to it.
You probably don’t have to be a purist about it, but avoiding grains is good, and if you must have them, go for whole grain. Just don’t get too wrapped up in studies that try and fool people with confounding data!Share on Facebook