Review: The Mystery of Energy Compensation (eg, why CICO is not accurate)

(Bob M) #1

This is a review that discusses possible reasons why the body adjusts to exercise by decreasing its energy output. According to CICO, if you burn 300 calories, that’s “calories out (CO)”, and if you do not increase “calories in (CI)”, you should burn fat/lose weight. The problem is that this is not true. Instead, the body compensates by reducing energy expenditure for some or all of that exercise.

This is a (bit complex) review that discusses the mechanisms that might occur to reduce energy exposure:

If you decide to read this, I recommend grabbing some paper and writing down the acronyms. An example:

These (and other) acronyms are used all the time, and it’s helpful to know what they are.

But that figure brings up an interesting point. If you’re trying to measure basal metabolic rate/BEE (basal energy expenditure), you have to be careful WHEN you measure it. If you measure energy expenditure before exercise, that’s the best time. If you measure after exercise, you get into this EPOC (excess post-exercise energy consumption) period. I’ve seen studies indicating that can last a while (even a day?).

He also shows a figure 3, where BEE and AEE vary over the day. So, if you’re not measuring at the same time each day, you’re potentially comparing two different results.

Anyway, it’s a fascinating paper on how the body might compensate for increased exercise by reducing energy expenditure. (One that I will have to read multiple times to absorb.)

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

Didn’t you recently also link a paper in another topic that demonstrated that the metabolism reduces BMR to compensate for increased energy expended when intake is reduced? More nails in the CICO coffin.

Thanks for your efforts finding these studies for the rest of us! :+1:

(Bob M) #3

Thanks, Michael, but I can’t take any credit. It’s the people I happen to follow on Twitter that find the studies.

I’ve reached the conclusion that everything is complex. That complexity is oftentimes hard for us to fathom, so we make shortcuts like “CICO”. But then that leaves out all kinds of exceptions. (And, let’s face it, CICO was never correct anyway, even though it does seem to make logical sense.)

But I think fat intake, protein intake, even – gasp! – carb intake for keto is complex. There’s probably not one solution, or maybe even only a few solutions.

I just highlight the studies I think are interesting and feed my own biases that there’s a complexity out there.


It’s a really interesting paper; thank you for linking it.

I can understand the desire for CICO to be the answer, but we’re not robots; try as we might, we don’t truly understand how many calories our bodies expend or the changes our body silently makes in response to changing intake / changing expenditure. This study details that brilliantly.

I’ve posted a few times about how eating vastly more calories (and losing fat at the same time) has caused me to feel warm. I have spent years being freezing cold because I was reducing my calories, thinking that would help me to lose weight.

So I know with my n=1 that CICO is not the be-all-and-end-all, despite many people claiming that it is - because our bodies are complex and seem to shut down certain processes if there’s not enough nutrition to spare.

Unfortunately, CICO works for almost everyone for a period of time - and then when it stops working (for instance, because we’ve lowered our metabolic rate), then the blame is placed on the individual rather than revaluating whether CICO is the correct paradigm.

Why are people so hell bent on defending CICO
(Doug) #6

Need to know calories in, Bob. Also, if you’re saying that 300 calories aren’t actually being burned, then we need to take that into account too.