Breakfast = carbs
Snack = carbs
Lunch = carbs
Dinner = carbs
Easiest way to get a grip of it, do as TTT said and work out your macros. Puts you right on track for what you want to achieve.
Without knowing what quantities, I'm Gunna say you aren't eating enough of the right macronutrient groups I.e. protein & fat.
Birds diet approach works for him, he has been doing it for years, fine tuning what he needs to get where he wants.....
As Markos' works for his lifters to get stronger.
Macros is just like asking someone for a workout plan. Someone has done the hard work and made calculations, all you have to do is plug in your numbers and presto, baseline guide on what macronutrients to eat.
E.g, 120g protein = eat at least a 300g steak a day.
50g fat = oils, fats in the steak, fats in the chips that go with the steak.
200g Carbs = oats, pasta, veges, fruit, yoghurt, roll.
It's still all the basics, eat animals and things animals eat preferably, but it points you towards how much of those.
1kg of meat and 2kg of veg, ain't going to be the same requirement for a 60kg person and 120kg person.