How can CICO and plateaus both be real?

FitAgainBy55 wrote: »

The answer comes in two parts, first we have to define a real plateau and then we can discuss the CICO model.

What is a real plateau
Stalls or even gains that occur over short periods of time (let's say 3 weeks or less) aren't real plateaus. Fat loss isn't linear and water weight causes lots of variations in our day to day weigh ins.

Real plateaus ARE CONSISTENT with the CICO model
The CO part of the model is NOT an absolute. It is an estimate. All models are wrong, some models are useful. There is a large amount of variability in CO for each individual. When faced with sustained calorie restriction over a period of many weeks, biological and behavioral adaptations can cause a large enough reduction in CO to stall weight loss when CI is held constant.

This is probably my favorite all time study on CICO. This quantifies the impact of behavioral and biological adaptations during long term (6 months) calorie restriction in terms of reduction in the CO component of CICO:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2634841/

Here are some highlights from the study:

1. Resting energy expenditure was 6% lower after 6 months of 25% calorie restriction
2. TDEE was reduced by several hundred calories (AFTER accounting for measured sedentary energy expenditure) in the groups that were losing weight with calorie restriction only. The group that created a deficit with 50% exercise and 50% diet did not have a reduced TDEE.

Here is there summary:
Note: CR = Deficit created via calorie restriction, EX = Deficit created via exercise

"Therefore, this study supports a ‘metabolic adaptation’ in response to weight loss in humans and demonstrates for the first time a reduction in all components of daily energy expenditure with dietary-induced weight loss, including the level physical activity. Importantly, CR in combination with exercise (CR+EX) did not result in metabolic adaptation while inducing similar changes in body composition as with CR alone."