Did they really lose weight whilst eating at calorie maintenance just because they were told they were dieting?
Yes, but deviation from true calorie maintenance likely occurred unknowingly due to the placebo effect.
One study does not refute the laws of thermodynamics, however it does serve as a reminder to us that this stuff is complicated.
Humans are not machines that respond to a series of inputs with predictable outputs.
The human body is a complex and ever changing ecosystem of interwoven psychological, emotional, social, biological factors + more.
Placebo has power and it's not always a negative thing.