It’s actually better for your body to eat smaller meals more frequently. It doesn’t put so much strain on your digestive system and helps to keep your blood sugar stable. When you get hungry, try munching on avocado, olives or other veggies and the yoghurt or kefir like Raster said.
When you’re on a low-carb diet like this, your body uses fat for fuel, so instead of extra sardines, why not extra olive or coconut oil? Supplementing fish oil will give you extra calories, as well as a lot of other health benefits. Avocado has a decent amount of fat too.
If you’re active, you do want to get a decent amount of protein to avoid muscle loss, but at the same time it’s the hardest nutrient to digest, and excessive animal and fish proteins can cause problems for candida sufferers. You want to get the amount of protein you need, and avoid going over that amount.