I’d be careful eating in a surplus to fuel subliminals. If you are someone who gains weight easily, don’t do it. If you are eating in a surplus, make sure you are lifting weights and moving more. Some people don’t gain weight so easily, maybe you don’t either.
The brain does burn a lot of calories, but it is similar to a stressful exam period where some students start eating more food and gain weight. I would first focus on doing things to reduce stress. Make sure you take rest days and washouts. Get enough sleep. Meditate. Improve the quality of your diet. Take supplements like omega-3’s and D3.