Diet is a very individual thing, I've tried several diets in the past, (I worked out for 10 years, then took off 7 to develop my career) Now I'm back in the gym for one year and in the best shape of my life. Last year I was the fattest I have ever been.
I like the Keto diet, and mine goes as follows:
Day 1: High Protein, Moderate Carbs, low fat. (balanced day)
Sample of one meal would be: Chicken breast, sweet potato, brocolli
Day 2 & 3: High Protein, Low carbs, Low fat. (Low carb days)
Sample of one meal would be: Chicken breast, 2 brocolli spears
(sometimes just protein, like Tuna, Salmon, etc.)
Day 4 High Protein, High carbs, high fats. (eat a lot day)
2 T-bone steaks, Sweet potato, fruit
I also cycle my workout to accomodate my diet, since I train at night, what I eat really determines how much energy I have to train, so I train legs on the high carb day. rest on the balance day and days 2 & 3 train upper body.
I'm in my 6th week, it's working wonders for me! I'm very pleased with my results. I train with my younger brother, he can't lower his carbs as much as I do, he gets too tired and flat.
But some may need more high carb days, some need more low carb days. Take the others advice and consult a diet coach, or at least get some info from here or get one of these publications they talk about, that will be a start, but monitor your progress with photos and I personally use the calendar on my computer to keep track of what I eat and what day I'm on, body weight, workouts, etc.
Oh, I do no cardio what-so-ever. I'm not against it, but I've tried it in the past and it just made me smaller and softer. I let the diet cut the fat and train as heavy as possible, but my workouts are faster, less rest between sets, except for when I squat. Everything else is fast pace. Again, this is what I'm doing you have to try different things to see what does it for you, good luck, keep us posted!