I came across quite a few people unable to loose significant weight even though drastically decreasing their caloric intake. The so called weight thermostat is believed to be the mechanism which regulates bodyweight homeostasis and defends fatloss. Supposedly, it may work the other way around. The article may have been already cited by AlPater.
The application to human beings is unclear, although many people are anecdotally suggesting not to decrease calories too much in weightloss diets and to 'cheat' regularly, to deceive the homeostatc mechanisms of AGRP neurons.
Application to CR is evident, some people may find unsourmontable difficulties to hit the target threshold weight linked to onset of CR.
Luke K Burke, Tamana Darwish, Althea R Cavanaugh, Sam Virtue, Emma Roth, Joanna Morro, Shun-Mei Liu, Jing Xia, Jeffrey W Dalley, Keith Burling, Streamson Chua, Toni Vidal-Puig, Gary J Schwartz, Clémence Blouet.
mTORC1 in AGRP neurons integrates exteroceptive and interoceptive food-related cues in the modulation of adaptive energy expenditure in mice. eLife, 2017; 6 DOI: 10.7554/eLife.22848