Nutrient paste is a source of food that's commonly served to the Psyches in Psychelia in the EMPATH: The Luckiest Smurf story series. It can be described as a very thick and tasteless porridge -- or, as Greedy Smurf would put it, "porridge smurfed from a bag of cement". According to Empath and Polaris, its tastelessness is demanded by the central tenets of the Psychelian belief system that Psyches are not to eat or drink anything that has a flavor to it. It is usually served only once a day, as Psyches do not need to eat as often as Smurfs do. Empath's serving is usually modified to include the nutrients found in smurfberries.
Nutrient paste is the least favorite thing that Greedy likes to make for anyone, due to both the constant difficulty of perfecting a recipe that only the Psyches knew how to make, and also due to Greedy's preference for making delicious food that actually has a taste to it. It is also Empath's least favorite food to eat, since his appetite for it has been spoiled when he started eating actual smurfberries. From the time that Polaris was cured of an inherent degenerative disease caused by his disconnection from the mindlink of the Psyches, using Smurf essence as part of the cure, his dietary requirements changed to the point where he no longer need to eat only nutrient paste.
The only thing not replicated in the Smurf Village recipe for nutrient paste is a psychotropic medicine called psychelium. It is administered by the Psyche Master to all Psyches, which is used to help suppress all emotional expressions, including sexual desire. Surprisingly, over time, Empath became increasingly immune to the psychotropic medicine.
Nutrient paste is based loosely on gruel that was served to the orphans in the workhouse in Charles Dickens' Oliver Twist, and on the "baby food" paste that was given to RoboCop to eat in the RoboCop film series.