More Thoughts on Macronutrient Trends

More Thoughts on Macronutrient Trends

I had a brief positive exchange with Gary Taubes about the NuSI post.  He reminded me that there's an artifact (measurement error) in the USDA data on fat consumption in the year 2000 when they changed assessment methods.  Here are the USDA data on macronutrient consumption since 1970, corrected for loss (28.8%) but not corrected for the artifact:

The data suggest an increase in fat consumption, although I didn't make that claim in the last post because I'm aware of the limitations of the dataset.  What I wrote is that the data don't support a decrease in fat consumption, which is accurate. 

Looking at the graph above, you can see the abrupt increase in fat consumption in 2000.  I corrected the data for this artifact in the graph below:  

When you correct for the artifact, the data show very little change in fat consumption between 1970 and 2006 (small increase).  This is consistent with NHANES survey data, which also show essentially no change (slight decrease).  Each dataset has its own limitations, but I prefer the USDA data for most things because they're yearly, more detailed, and more accessible.

Here's a graph of macronutrient intake since 1909, adjusted for loss and the artifact in 2000:

The data from the first decade or so are somewhat sketchy because they were estimated retrospectively.  The quality of the data improve progressively from the early 1920s through 1940, as more commodities were tracked.

The graph suggests that fat consumption has gradually increased over the last century (+ 30%), carbohydrate consumption has decreased and then rebounded (currently - 6%), and protein consumption has increased modestly (+ 10%).

The modern "obesity epidemic" began in earnest between the 1976-1980 and 1988-1994 NHANESsurvey periods, and corresponded with an increase in calorie intake.  According to the adjusted data, this increase was 350 calories per day since 1970.  65 percent of the increase in calories can be attributed to carbohydrate, 24 percent can be attributed to fat, and 11 percent to protein.

The excess carbohydrate and fat came mostly from processed refined foods such as sweetened soda and processed snacks.   

A Note about Reproducing Materials Published on Whole Health Source 

I've noticed instances of other bloggers using my original materials without attribution (e.g. graphs).  My copyright policy, as always, is on the sidebar to the right (bottom).  Here's what it says:

Please feel free to reproduce the contents of this blog, on the condition that you:  

1) Attribute the work to me
2) Provide a link to the page where you found it
3) Do not use it for commercial purposes

I think it's a pretty generous policy, so please respect it like most people have.  Since the graphs in this post are probably going to end up all over the Internet, I've added my name to each to facilitate this.