Actually, it is for some people. My daughter has a seizure disorder that is very sensitive to sugar, specifically sucrose and glucose ( perhaps also fructose). We discovered this by removing sugary foods from her diet, with remarkable effects. Further validation came when she had to be on intravenous feeding while in ICU several years later. Of course, i.v. feeding solutions are high in glucose, and she seizured hard. These were controlled with higher doses of levetiracetam, and since then she’s had no seizures on a very low maintenance dose. This made me realize how refined sugar really can be “poison”.