I suggest a better response to CICO is not that this isn’t true but that it is hard for a variety of reasons. One’s response to CICO ought not be to deny basic physics. There was a comment that it is basic physics that CICO is true and it got pushback. My post was to point out that the pushback against that comment were wrong in the sense of not actually disputing CICO.

The responses should have been of the form, “Absolutely but this is very hard for some people for the following reasons…”. That changes to one part of the equation can have unintended consequences that change the other part.

Here’s a quote from Kevin Hall, who does metabolic studies at Harvard:

>The problem is that CICO as the law of energy conservation is NOT a model of obesity. It's conflated with the straw-man "Conventional Model" described by Ludwig: independent, unregulated intake and expenditure implying that getting fat and treating obesity are all about willpower

It's not so much that I would dispute the physics, but I personally wonder about digestion. This strict cico model seems to make the assumption that every digestive system extracts the same amount of energy from the same foods, which I find unlikely but am certainly not an expert. If I eat a bunch of grass, I am pretty sure I'll probably get sick and have some unpleasant bowel movements but I won't draw many calories from the grass. Unlike a cow.

Personally though, I find it rather easy to maintain a particular weight. I just wear pants with the right waist size and if they feel tight I take it easy on eating for a day or two. I have had the same weight +/- 1.5kg for 20 years. Losing weight beyond my comfortable baseline is exceedingly difficult though.

That's not really how I interpret it at least. I think its assumed there is no one with a perfectly efficient digestive system, and that there is variance in efficiency based on a plethora of factors. However, that efficiency rate hardly matters. You are in effect a car. Some people are hybrids, super efficient perhaps, while others are SUVs guzzling gas to go the same distance. That being said one thing is true for all of these cars: if you put in 9 gallons instead of 10 gallons into the tank, you will go for less miles than if you put in 10 gallons. In other words, if you are being accurate about measuring your calories in (the gas) and you are measuring your weight (miles driven), you can adjust the input calories to effect your output weight. Exercise then is like driving in low gear with the engine at a high RPM; you are burning more calories in a given amount of time just like you'd be burning more gas in a given distance running at a higher RPM.