**Monitoring and Revision:** It is important to observe how the meal plan is working out for me, and based on this, adjust the plan. Your feedback will be essential in making the necessary dietary alterations to bring out the best results.

**Schedule:** This meal plan will be followed routinely until otherwise advised by you, the nutritionist. The aim is consistency and precision in hitting the '500'-calorie target for breakfast.

**Conclusion:** Precision and accuracy are of utmost importance when it comes to counting calories and sticking to a target. Any minor deviation may have a notable impact on the overall nutrition plan. With this detailed approach in mind, I will also keep reminding myself about my dietary goals to ensure that I do not stray away from the targeted '500'-calorie breakfast meal plan.

Here is a sample Breakfast meal plan for approximation:

- Banana (1 medium): 105 calories
- Apple (1 medium): 95 calories
- Mango (1/2 medium): 150 calories
- Watermelon (1 cup, diced): 45 calories 

Total 'Breakfast' calories = 395 calories

For an additional 105 calories, you can add:

- Fat: Half an avocado: 60 calories
- Carbohydrates: Half a slice of whole grain bread: 35 calories 
- Protein option: You could have part of your protein portion in breakfast. 

Now, the grand total will be 500 calories. 

The nutritional breakdown is as follows:

- Fat: Avocado provides 4.5g of fat, which is 9% of the grand total calories.
- Carbohydrates: The carbohydrates in fruit and bread provide ~85g, which is ~68% of the grand total calories.
- Protein: You can get around 5g of protein from fruit, avocado and bread which is ~4% of the grand total calories.

This is a rough draft, and individual nutrients might fluctuate depending on the size and ripeness of the fruit. We can adjust sizes and perhaps add additional protein sources to meet the target macros (fats, carbs, proteins). Your feedback on this initial plan will ensure that we refine and optimise the meal plan to meet specific dietary goals.