Experts vs Trial and Error

Writing in the Wall Street Journal, Nina Teicholz casts doubt on the ‘conventional wisdom’ that saturated fat causes heart disease (thanks to The Pretense of Knowledge for the pointer).

Of course, Gary Taubes laid out much of the same story line in his book, Good Calories, Bad Calories. I mention it here and here.

Teicholz mentions President Eisenhower’s heart attack. She didn’t mention the additional detail that Taubes provided. His doctor cut his cholesterol intake and his cholesterol levels went up.

Teicholz, perhaps, summarizes the beginning of the Type II diabetic and obesity trends when unreliable health studies were used to guide the American diet:

As Harvard nutrition professor Mark Hegsted said in 1977, after successfully persuading the U.S. Senate to recommend Dr. Keys’s diet for the entire nation, the question wasn’t whether Americans should change their diets, but why not? Important benefits could be expected, he argued. And the risks? “None can be identified,” he said.

This is where I’ve gained much appreciation for what Nassim Taleb identified as the expert problem, as he describes here.

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Random Considerations for Fitness New Year’s Resolutions

I hadn’t thought of these before and thought they were interesting and sharing for your consideration.

I think they both stemmed from Taleb’s Antifragility book, but I’m not so sure about the first one.

1. It’s good to eat a random variety foods rather than the same things every day, or week. Why? All foods contain some natural toxins. If you eat the same things, the levels of those same toxins can build up  in your body.

I have no idea if this is true but I don’t know of too many (any?) downsides in having more variety in a diet, so why not?

2. I just read this one in Taleb’s book (it triggered my memory of #1) and made me think of a personal experience:

Randomness in the quantities and macro nutrient composition (fat, protein, carb) of your daily intake may also be good for you.

Dietary guidelines and diets assume consistent quantities and proportions of things at each meal, or each day. I think we automatically assume that too.

But, Taleb contends our bodies get stronger, more fit, with a bit more randomness. Lots of carbs one day, all protein and fat the next. Skip a meal here and there. He notes most dietary studies are based on consistent intakes, while the effect of random intakes have escaped even being a consideration in those studies.

A personal experience:

As I lost weight 12 years ago, I allowed myself one splurge every five to seven days. I figured if I was “good” the rest of the days, one bender wouldn’t hurt too bad, and would help keep me good the rest of the days.

I would splurge on random things — but it was usually carbs. One week might be a banana split. The next might be a pasta dinner.

I expected to hop on the scale the day after my splurge and see a temporary reversal in my progress. Yet, I was often surprised, on occasion to see the positive progress had continued, sometimes accelerated.

I can’t say for sure how many times that happened. It wasn’t even something I considered that could be a cause. But, it happened enough for it stick in my memory.

I never thought much about that. I thought those were flukes. I was sure there was no way that the splurge would help me temporarily. That didn’t fit with any mental model on diet and weight loss that I knew about.

Then I read #2 and it made me wonder. Maybe that 5-7 day splurge helped more than as a reward for being “good” the rest of the time. Maybe it even played a bigger role in my overall weight loss than I ever imagined.

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More Signals v Causes

I came across a couple good examples of confusing signals and causes this week.

1. Does language cause culture? In this case, do languages that “grammatically associate the future and the present, foster future-oriented behavior”? More likely: Language is shaped by culture. Cultures that save for the future evolve words that convey that part of their culture.

2. Does consumption of processed meats shorten life?  More likely: Folks who eat things that have been considered bad for you for the last 50 years also have other unhealthy behaviors that may contribute to shorten lives.

Thanks to the What We Think and Why blog for republishing my earlier Signal v Causes post.

I’m skeptical of the chocolate study

While my own biases really, really want this one to be true, I am just as skeptical of the study that says: Eating Lots of Chocolate Helps People Stay Thin,” as I am about the red meat study.

I have many of the same concerns. The main one is that the folks who eat a lot of chocolate may simply lead healthier lives.

Other concerns I have about the study include:

  • Just like in the red meat study, is that the amount of chocolate eaten is determined by self-reporting, which is not reliable. For example, unhealthy people may simply have under reported their chocolate intake.
  • Small sample size. The study contained 1,000 people. That’s small.
  • The average age was 57 and we don’t know how long these folks have had their chocolate habit. In 57 years, there could be many more things that influence health than chocolate consumption.

So, it’s possible that this research shows that healthier people in this group of 1,000 said they eat more chocolate than the less healthy people, which really doesn’t mean much.

I will, however, give the researcher credit. She wasn’t nearly as pompous about her findings as the red meat researcher.  When asked if we should all eat more chocolate she responded:

Our findings – that more frequent chocolate intake is linked to lower BMI – are intriguing, however it is not a siren call to go out and eat 20 pounds of chocolate a day.

Though, I’ll point out that while linked is a better word than causes, I think the statistically-challenged will not appreciate that fine point and will likely treat the two words as synonyms.

I’m skeptical of the red meat study

We’ve all heard ‘meat and potatoes’ dishes referred to as a ‘heart attack on a plate.’  What we may not have suspected was that it was actually the potatoes that might do the damage, not the meat.

But, I’m sure that’ll be a hard sell after the recent Harvard red meat study.  It’s been getting much press lately. Most press reports say something like: “Eating a lot of red meat will kill you. Guys from Harvard say so.”

The first day that this came out, I asked an associate to identify potential problems with the study. We have to pick apart similar studies all the time for our jobs. I thought this would be good practice. He did a great job.

And so did CNN for including his primary concern in their online article about the study. Something I haven’t seen other media outlets do yet.

Unfortunately you have to make it to the last two paragraphs of the CNN article to read it. Here it is:

Studies like Pan’s are inherently iffy due to red meat’s unhealthy reputation, which makes red-meat consumption difficult to tease apart from a person’s overall lifestyle, Lindeberg says. “Red meat has been perceived as a villain for many years, and people who avoid red meat take all sorts of precautionary measures for their future health,” he says. “It is not possible to statistically adjust for all of these measures.”

Sure enough, Pan and his colleagues found that the men and women in the study who ate the most red meat also tended to be heavier, less physically active, and more likely to smoke and drink alcohol than their peers. However, the researchers did take those and other factors into account in their analysis.

In other words, the researchers may have really found that overall unhealthy people die prematurely. Wow.

For those who would like to know more about the flaws in the diet and health research, I recommend reading Gary Taubes. He has done a fabulous job in his book Good Calories, Bad Calories at casting credible doubts on past health studies like this one, which form the foundation of the of diet and health ‘conventional wisdom’ that has helped drive increases in obesity and Type II diabetes.

Taubes’ book is big. If you don’t have that kind of time, download and listen this Econtalk podcast that had Taubes as the guest (also available on iTunes). The podcast is an 1 hour and 22 minutes. Listen to it while you workout. I do.

Not only does Taubes cast doubts on these studies, he demonstrates that some of these studies never actually proved the hypotheses (that are now conventional wisdom) like “fat is bad for you”.  When the researchers with these hypotheses didn’t prove them, they’d just say, “well, this study didn’t show it, but we’re certain that it’s just a matter of time that other studies will.”

Over time, it was the domineering personalities of these researchers and political connections that eventually thrust their unproven hypotheses into the realm of conventional wisdom.

The nanny government of the 60s and 70s felt they needed to give guidance on healthy eating (hmmm), so they took the conventional wisdom from these researchers (it’s easy to sell BS to the public when you can say things like “research suggests”, even when it doesn’t) and created the food pyramid, which has helped wreck our health and medical system.

For making it to the final paragraphs of this post, I’ll reward you with the hypothesis Taubes’ has to explain our declining health: sugar & flour. Especially refined sugar, starches and flour. Taubes thinks these boost insulin levels, which tells the body to store fat.

When you see an overweight person, don’t think about how much they eat. Rather think about how much sugar and starch they eat. Don’t believe Taubes? Cut back on your sugar (candy, cookies, mochas), flour (bread, pasta) and starch (fries, chips) for a few days, eat a little more fat, protein, fruits and veggies and watch the scale.

“Letter on Corpulence, Addressed to the Public”

William Banting wrote a 16-page diet book in 1863 with this name.  I love that name.

It appears he had it all figured out then.  His advice turned out to be the same advice that a) helped me lose weight and keep it off (going 11 years now) and b) recently helped me improve my cholesterol levels.

His advice:  Eat less sugars and starch, eat more proteins and fat.  Why?  Because too much sugar and starch throws off your hormones and tells your body to store fat.  Proteins and fat don’t.  In fact, too much sugar and starch will lead to diabetes.  Hello, diabetes epidemic coming after several decades of sugar and starch consumption!

I’m reading Gary Taubes longer than 16-page book, Good Calories, Bad Calories.  If you don’t have time to read the whole book, read the Prologue.  In it, Taubes gives great highlights on the evolution in the diet world since Banting’s book.

In the rest of his book, Taubes exhaustively reviews the “scientific” literature on diets to show that much of the conventional diet wisdom (e.g. government guidelines, the calorie balance equation, eating a low-fat diet) actually has no scientific basis.  Shocking.

But, for your own health, here’s the summary:  Follow Banting’s advice.

When I lost weight, I attributed my success to a lot things because I changed a lot of things.  I balanced my calories.  I ate more often.  I watched my portions.  I reduced mindless eating.  And, I increased my intake of fat and protein and decreased my intake of sugars and starches.

In his other book, Why We Get Fat, Taubes said that people with weight loss success like mine tend to confound all the reasons, but there’s really just one, the last one.

It’s worth experimenting.  Cut back on sugars, breads and starches in your diet, eat a little more fat and protein and watch your scale.