Gaining

I got some bottled gain shakes and I think the dairy gave me tummy rumbles. Whole milk did too. I suspect it's lactose intolerance.

What are y'all's favorite dairy-free fattening options?

Oat milk is a great alternative and in my opinion tastes the best out of the milk alternatives and is still quite high in calories. Alternatively, I know where I live you can get lactose free cream which doesn’t upset stomaches as well.

Nut butters (peanut butter, almond butter) and oils are also good dairy free fattening options

I use Smart Balance in all my recipes that call for butter. It tastes the same but won't give me the runs. Coconut milk is also great for sauces and curries, especially if you want to experiment cooking Indian and Asian food. (Which is not the most fattening cuisine out there but sometimes you gotta get some variety just to keep things fun and interesting.)