Hi Lucy I know this reply is a long time after your question but I've only just joined, I'm vegan and am managing the lean in 14 plan quite easily. I recommend using
macros, I used the free macros calculator on the train eat gain website to work out how much protein, carbs, fat and calories I need daily then I log my meals on cronometer (app) to track. It's a bit of a faff at first but it gets easier and you can enter whole recipes of things you eat regularly. I swap meat fish etc for vegan quorn, tofu or tempeh. You do need to eat a lot though!! My portions are huge and I'm still usually slightly under my recommend calorie intake but I'm not hungry and tempted to eats loads of bread ( my nemesis ha ha) I also use a vegan protein powder to add to smoothies. I hope this helps