I would tell you to eat meat, but meat needs salt to sing.
I would tell you to eat pasta, but pasta needs salt to sing....
However, rattling around in my memory is something that could be a useful tip. Making your own fresh pasta will almost guarantee that you'll gain weight (cause it's so tasty and filled with eggs and carbs to boot) but the problem of salt remains...IIRC, a long ago friend had some trouble with salt intake but was a gourmand, and used a teaspoon of fish oil per batch of pasta dough to balance out the flavor and make it sing as if it were salty.
You don't really need a pasta maker to make pasta if you're comfortable using a rolling pin and sharp knife, but the makers can be had for reasonable prices these days.
Mixing in various herbs, spices and finely chopped veggies like sun dried tomatoes could give you a nearly endless variety of a proven weigh gaining food that would otherwise be monotonous if store-bought.