Honestly I Been trying to figure this out for a while since I lift weights and I lost 30lbs fighting candida but it’s better u reach a decent weight depending on height and gender. Worry about gaining weight later on. I think if you focus on gaining weight you might end up in a cycle where your candida might not improve. Just my opinion. Fighting candida is hard enough don’t put too much pressure on yourself. Stick to the veggies and healthy fats like avocados, eggs and coconut oil and after a couple months try to gain weight with the appropriate foods. Hope this helps and stay positive.