Here are some great tips on how to gain weight on a plant based diet from PCRM.org (for those who may be underweight):
1. Drink your calories in the form of smoothies and pure juice.
2. Focus more on beans (especially tofu and tempeh) and grains (even processed like pasta and bagels), which pack in more calories than whole fruits and vegetables.
3. Eat nuts and seeds (1-2 oz per day).
4. Add avocados and coconut milk to your smoothies
In addition, the vegan diet for the ultra athlete outlines a high calorie plant-based menu that shows how to consume a lot of calories from plants.
Other Source: Brenda Davis, Becoming Vegan
