Lean animals? I'm highly skeptical that it applies to these pigs. A single kg of fat has ~7700kcal, and unlike self control, that's something they have plenty of.  Reminds me of the Minnesota Starvation Experiment: significant increases in depression, hysteria and hypochondriasis, one of the patients amputated 3 fingers with an axe, but every single one of them lost weight on a caloric deficit. 70 years later, you can still find retards claiming otherwise on the internet.