Calories-in, Calories-Out (CICO) must die.

This post is a reaction from reading Adele Hite’s brilliant and hilarious post on a talk by Walter Willett: Walter Willett is the Chair of Nutrition at the Harvard School of Public Health, and is recognized as a leader in the field of nutritional epidemiology.

Please go read Adele’s post. It’s a short read. Then come back to read the rest of this post.

I know it’s “just rats”, but I had 8 rats that had become obese on a refined foods (REF) diet over a 9 month period (well, they became obese in two weeks, and maintained it over the rest of the 9 months).

I then put them into cages with access to a running wheel for 5 weeks. And I switched half of the rats to a healthy control (CON) diet.

What happened?

The rats on the REF diet continued to increase in weight while the rats on the CON diet lost weight.

Weight in running wheels

Okay, that’s expected. Eat a healthy diet and lose weight.

According to Willett’s argument, the CON rats should have lost weight because they exercised more and ate less. Likewise, the rats that stayed on the REF diet should have ate more than before being placed in the running-wheel cage, and should not have exercised much at all. This is classic CICO.

Okay, let’s take a look, first at amount of food consumed:

Food consumption in running wheels

Doh! BOTH groups of rats consumed less food after being placed in the running-wheel cages. Even the rats continuing to eat the REF diet and gain more weight over the 5-week period consumed LESS food than before being placed in the running wheel cages!

The same story emerges when we plot energy consumption per rat by diet condition:

Mean Energy consumed in running wheels

Well, obviously the fat rats on the REF diet must have been stupendously lazy and not run in the wheels at all, otherwise how could they lose weight while eating less? On the other hand, the rats switched to the CON diet both ate less and exercised a lot more in order to lose their weight. Right?

Mean distance ran in running wheels

Oops! The rats switched to the healthy CON diet actually ran less distance per week than did the rats that stayed on the REF diet!

Holy balances and scales Batman! What gives?

Perhaps CICO and its adherents (WW and the good folks at the Harvard School of Public Health) are wrong?

Oh wait, but these are just rats. This scenario would NEVER occur in humans…


Author: aaronblaisdell

I am interested in animal cognition and behavior. How do animals build and use representations of their world? I use Pavlovian and instrumental conditioning procedures to dissect this question. My work addresses a number of research questions at the interface between associative and cognitive processes. How do rats make causal inferences? What other rational processes do rats use? How do pigeons learn and integrate spatial maps? What are the sources of behavioral variability and what is its role in problem solving? Recently I have begun to study attentional processes in hermit crabs, such as habituation and sensitization. A second interest of mine is in how human ancestry and evolution can inform us about our health and well being. In particular, our modern world is quite different from that of our ancestors, to the detriment of our physiologies and biochemistries.

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