While this is probably mostly true, there is good science indicating that certain hormonal portfolios "hold" onto calories better than others. There is a reason power lifters are spiking insulin post workout, people are taking steroids, and medical conditions can make you fat.
If my mother wants to cut weight, I'm telling her this. If an athlete has to make weight for a fight, this is a stupid way of thinking. At the end of the day, calories in calories out is an objectively good rule of thumb. It's not the be all end all rule though.
Medical conditions don’t cause mass to appear from nowhere that goes against the laws of physics. Yes medical conditions can cause your metabolism to slow down - decreasing calories out.
> While this is probably mostly true, there is good science indicating that certain hormonal portfolios "hold" onto calories better than others.
Yes, that's true, but too many people believe that hormones have a whole number multiplier effect when in fact they probably just nudge TDEE by, what, (off the cuff here) ten percent plus or minus? Maybe less?
Is that enough to significantly reduce a person's margin of error when they're doing CICO, particularly as they get closer to their ideal weight?
Absolutely.
Does that mean they'll get fat eating less than a thousand calories a day because hormones?
If my mother wants to cut weight, I'm telling her this. If an athlete has to make weight for a fight, this is a stupid way of thinking. At the end of the day, calories in calories out is an objectively good rule of thumb. It's not the be all end all rule though.