To be frank I eat rice in every meal except breakfast and I had a hard time gaining weight. But it depends on how many meals you eat and what do you eat alongside with them, if you eat three square meals with rice in it, its unlikely that you will gain any weight as rice isn't a really a good source of calories. However it does give you a fair amount but rice can fill your stomach for some time so you're not gonna be craving for much food later.
There are many factors that you should take into account on rice:
-What type of rice is it?
-How much rice are you eating?
-What are the nutritional values on the dishes alongside with rice?
-How much of these dishes are you taking in?
i have 5 meals per day 4 of the meals consist of white rice about 1 and 1/2 cup of rice per meal and my main dish have a rotation like this beef,fish,chicken,pork,egg and the last or the 5th meal is spaghetti w/some cheese and egg sometimes i change this to bread w/tuna and egg
and with milk i also add banana if there is any. i also drink 8glasses of water or more