Weight gain supplements that work?? in Health & Nutrition Programs Posted December 6, 2012 There really isn't anything that's a specific vegan-friendly weight gainer out there. That being said, not losing weight is about keeping calories up - easiest way to do that is pack in some additional high-calorie foods if you're worried, even just having a few handful of cashews, almonds, peanuts, etc. can easily give you another 500+ calories of protein and fat very easily without filling you up too much. I'd suggest considering nuts and nut butters by themselves or nut butter blended in with smoothies or protein shakes to pack in the calories, a cheap and easy way to make sure you're getting plenty for what you need.