Yeah, we’re aware that the laws of thermodynamics must be followed. The study clearly showed that if you set CI to zero, and CO remains nonzero, you lose weight.

CICO is science, but your CO can change based on your CI and there are cases where it’s very hard to keep CI down. For an example, I have ADHD, it’s legitimately extremely difficult to keep track of what I eat, eating one meal a day was about the only thing that helped. I believe I was also prediabetic (based on my glucose levels before my weight loss) and eating a small meal, particularly if rich in carbs, made me go hangrryyyyyyy later, but in a fasted state I was completely OK. Now I’ve lost something around the neighbourhood of 30 kilos/65 lbs and don’t need to do one meal a day anymore, because I feel sated from much less food AND stay sated way longer.

This is why different people need their different tricks for weight loss. Find out how to reduce your hunger first and foremost, then focus on actually reducing calories. If fasting leads to being able to handle caloric restriction, it’s awesome. If not, try something else. But don’t restrict calories in a way that makes you continuously feel hungry, because that just won’t work long term.