[jacques_chester]

The term used these days is "adaptive thermogenesis". You can browbeat it anyhow by sufficiently undercutting caloric intake that the body can't down-regulate enough to cover the deficit. A much safer and easier way to do it is either to use a moderate deficit (studies of athletes show that with identical exercise and identical protein intake, athletes on a 500kcal deficit retain more strength and lean mass than athletes on a 1000kcal deficit) and do exercise, at least some of it with weights.

There's also the "rebound effect", which the Minnesota Starvation Experiment gives us insight into.

People stop dieting and then resume ad libitum eating. They gain fat faster than lean tissue, because gaining fat is easier than gaining lean tissue. Net effect: BF% worsens compared to baseline.

The key is not that "diets don't work, look, they make you fatter"; rather, it's that people see diets as something you do once and then stop. What's actually necessary is ongoing control of food intake.