3 month old kittens eating less

Hi I (22 f) recently adopted 2 kitten sisters at 8 weeks old. I had them spayed a couple weeks ago and thry are eating a bit less. When I got them, they would eat 3/4 of a can in one sitting twice a day plus dry food I would leave out. After the spay, they both eat 1/4 of a can of wet food twice a day and maybe 1/4 cup of dry food throughout the day. Is this normal? They are otherwise doing great, playing and drinking well and energy levels are great. Their poops are normal too and they are at the right weight but I am constantly worried there is something wrong or that they will start losing weight.