Sugar High is a Construct of the Government

From Kokorodatabase

Once Cherry learned that sugar does not, in fact, make one hyper, Shirogane Ryou began to lecture the residents and patrons of Cafe Mew Mew every time they brought up sugar high. Plum became very irritated at the notion that her precious method of making people hyper might not be real, and went into hyper-denial. But who knows? Maybe in Kokoro, it actually is real...