Can you gain muscle without gaining weight?!

Yes you can gain muscle without gaining weight. Some people do gain both muscle and weight though. It just depends on the person. There was a time when I was trying to lose weight, so I ate really healthy (monitored portions, calories, and food choices) and I was working out 6 days a week doing both cardio and weight training. I lost 20 pounds and noticed a difference in muscle tone/definition.

By the way, whoever gave me a thumbs down, I don't care...I'm the one getting a 2 bachelor's degrees in Nutrition and Food Science. Also, no amount of protein is gonna make your muscles bigger. That's what weight training is for. Excess protein intake turns to adipose tissue (body fat) and the part that doesn't will get excreted in the urine in the form of nitrogen (nitrogenous waste).

I'm a Nutritionist and soon to be food scientist.

You probably lost some fat that you didn't really notice. You can have fat distributed over a large enough area that it isn't very thick, so when it goes away you don't really see a difference.

nope, if you gain muscle, you are gaining weight. in the process, you might be losing fat, and it has been at a rate that is just enough to compensate for your muscle gain.

No not unless you are losing fat. Muscle weighs more that fat, so by gaining muscle you gain weight

you cant, you gain mass either way, which weighs