Friday, January 13, 2012

Why we get fat... according to Gary Taubes



I had the book Why We Get Fat:  And What to do About It recommended to me, so I read it over the holiday.  Frankly, if left to my own devices, I wouldn't have bought a book called Why We Get Fat because it's always seemed pretty simple to me.  According to Gary Taubes, it's not nearly as simple as we've been led to believe.  He's not a doctor or a scientist, but a scientific journalist.  I enjoyed his book, agreed with much of it, and disagreed with some, too.  It may be a bit premature for me to respond to his more recent book without first reading his previous and larger book, Good Calories, Bad Calories about much the same thing.   I'm anxious to read Good Calories, Bad Calories, but I'm also in the middle of a 90 day Bible challenge, homeschooling, etc. and don't know when I'll finish it.  So, since I have time now to respond to Why We Get Fat, I want to do so.  I can come back later and react to Good Calories, Bad Calories.

Taubes sketches the last 200 years of obesity research and concludes that what used to be common knowledge, that carbohydrates make us fat, is basically right.  He also goes to some trouble to argue that the lipid hypothesis which states that dietary cholesterol and saturated fat cause heart disease and atherosclerosis, is probably not true (except for the trans fats popularized ironically because of the lipid hypothesis, aka margarine as a substitue for butter).   He has to present this dual argument because one can be true, but not both.  Either carbohydrates are good and fats are bad (as we've been taught for the last 40+ years) or fats are good and carbohydrates are bad (as Taubes suggests).  Yes, this is a bit of an oversimplification, but it's basically what he argues. 

This is the food pyramid we all grew up with.  Is it backed by more scientific evidence or political pressure?
As you can see from the food pyramid above, if you're anywhere near my age, you were taught in school that the majority of your calories each day should be grains.  I took health in school, then I took physiology and chemistry and nutrition in college, then I took more physiology and biochemistry in graduate school, then I taught exercise physiology and sports nutrition in college.  So I don't take it lightly when I question whether this ideal that was taught to us, which I then taught to others, was backed by indisputable scientific evidence or whether it was more a product of political pressure and the industrialization of our food system (where big corn has more clout than say Joe dairy farmer).

Taubes is very persuasive, though it's obvious what he's trying to sell and to whom he's selling it.  He uses lots of case studies and anecdotal evidence, but it's not easy to go back more than 50 years and have a wealth of controlled studies to choose from.  For example, he argues that between 1910 and 1970 consumption of animal fats (butter, tallow, and lard) fell drastically while consumption of vegetable oils (corn oil, etc. including margarine) rose greatly.  Between 1910 and 1970 heart disease rose right along with consumption of vegetable oils.  As I said, Taubes is persuasive, so much so that I'm spending the weekend rendering lard from a 10 lb bag of clean pork fat I purchased from a local farmer, but still this argument wouldn't last 10 seconds in an academic setting.  The problem of course is there were many other changes in our lifestyle between 1910 and 1970.  I mean, that's practically like comparing the families of Little House on the Prairie with  the one in All in the Family.  Life changed in those 60 years, and most of us would probably argue that it wasn't for the better (the fat guy in the easy chair in front of the tv in All in the Family comes to mind)!  Taubes had already dismissed exercise as a factor in weight (something I'll dispute later), so I guess he thought he had his bases covered.  But, there could be a plethora of variables that could have contributed to the increase in heart disease from 1910 to 1970.  What about the mothers leaving home and joining the workforce, for example?  I'm sure this had a huge effect on our diet and other aspects of health during those 60 years. 

Taubes does cite lots of well-controlled experiments, too, but general sweeping arguments like the one above that are rooted in very little scientific evidence is what got us into this mess in the first place (if indeed we're in a mess, nutritionally).  It's hard for me to tell how much of his simplistic approach is because he wants his book to be readable and easy to follow or because he wants to sell us on the idea that fats are good and carbohydrates are bad.  (The title of his previous book makes me lean toward the latter.)

I can tell it's going to take me several more blog posts to sum up where I agree with Taubes and where I disagree with him and why.  Is this something anyone else is interested in? 

2 comments:

  1. I'm interested on what he had to say about exercise.

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  2. I love how you summed it up, AND put it in perspective. Lots to think on! Some of what he mentions I already knew, and some is a shady, grey area that I am not certain on. Hoping to learn more nutritionally....... period. Whether you talk more on this particular book or not, I would love to follow these posts on Health and nutrition. Although I love ALL your posts ;-)

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I'm an on-the-run mom to 6 kids who studied and taught exercise science in a previous life. I love all things running, nutrition, and health-related. I usually run at zero dark thirty in the morning and am often quite hungry before, during, and after my run, but I live a rich, full, blessed life with my children, family, and friends. My faith in God is my anchor, and looking to Him and His promises allows me to live fully even when life circumstances are difficult. While running gives me an appetite, my desire is to hunger and thirst for righteousness more than for physical food.