This question, whilst to a degree can be seen as "common sense" in some respects, has puzzled me in other ways.
Looking at the situations where Failure to Thrive (FTT) can cause death, even the Wikipedia article for it mentions mental issues as an endogenous cause, while there can also be one or more of both endogenous and exogenous causes.
I am intrigued by the mental issues for FTT deaths. What kind of mental issues, other than the obvious such as anorexia, can cause death due to FTT.
I am particularly interested in the cases where babies die due to FTT even though they have been fed, such as in orphanages.
Looking at a situation in Romania, I remember news reports during the dictatorship of Nicolae Ceaușescu, where there were large numbers of young children under 5 dying in orphanages due to FTT. I cannot find any reference to this online, however there is an APA report (Weir, 2014) which mentions institutional neglect causing developmental delays.
As well as developmental delays, can neglect through lack of emotional care be the cause of death through FTT? If so, how does the death occur even if nutritional needs are met?
Weir, K. (2014). The lasting impact of neglect. Monitor on Psychology 45(6), 36. Retrieved from: https://www.apa.org/monitor/2014/06/neglect