Are there any hadiths that prohibit looking at or counting food, based on the belief that doing so diminishes its blessing, such as the hadith mentioned by Lady Aisha?

There is no prohibition against looking at food. There are, however, narrations that indicate that refraining from measuring and counting food is a cause for blessing, as happened with 'Aisha, Jabir, and Umm Malik. Scholars interpret this to mean that blessings reside in the unknown, and that measuring might remove blessing due to reliance on conventional means and neglecting gratitude to Allah.

As for measuring for management and prudent foresight, without extravagance or stinginess, and with reliance on Allah, it is encouraged, based on the hadith (definition), "Measure your food; it will be blessed for you." Therefore, measuring itself does not remove blessing unless it is accompanied by something else, like exchange or testing. There is no contradiction between the hadiths about refraining from measuring and its circumstances, and the hadiths about measuring for blessing in livelihood management.