If you're wanting to gain size, you need to eat - more cals than you burn each day. If you have a lack of time, adding some weight gainer powder to a protein shake isn't a bad idea or mrp's and mrb's aren't a bad idea, either. In the afternoons, I add 1/2 scoop of ON's Serious Mass (low sugar) to 2 scoops of ON's Pro Complex in 12 oz of water. I'm getting around 600 cals, high protein and low sugar. I do that because it's quick and I don't have a lot time to eat a full meal. In the am, I switch it up. Protein shake with a small meal or protein shake with an Avid Source carmel peanut roll. 24 g's of protein with 22 g's of carbs and 6 g's of fat.
As far as fat goes, flax seed oil & olive oil are both good sources of good fat. A tablespoon of either is usually about 130 cals.
If time isn't a factor, then you're definitely better off eating solid foods. Either way, if you're eating properly, you can gain decent mass with minimal bf% gains.