Severe caloric restriction can induce significant weight loss and physiological changes.

“I mean you just take a step back right you can make anyone lean but just putting them putting them you know in prison and just only feeding them 1500 calories I mean we've done those kinds of experiment this this famous experiment the Minnesota starvation experiment right they basically this is didn't put people in prison but this is in World War II they took a bunch of healthy volunteers fed them 1600 calories a day just asked what would happen if you basically semi- starved people and unsurprisingly they lose an incredible amount of weight all they think about is food they basically their body temperature goes down their heart rate goes down they just become obsessed with food”