## Step 1: Define the optimization problem
The goal is to maximize the objective function: $6.35 \times \text{milkshakes} + 7.44 \times \text{oranges} + 2.49 \times \text{slices of pizza} + 7.43 \times \text{chicken drumsticks}$.

## 2: List all the constraints
The problem has the following constraints:
- Protein constraints:
  - $4 \times \text{milkshakes} + 1 \times \text{oranges} + 5 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 90$
  - $4 \times \text{milkshakes} + 5 \times \text{slices of pizza} \geq 8$
  - $1 \times \text{oranges} + 5 \times \text{slices of pizza} \geq 10$
  - $5 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \geq 20$
  - $4 \times \text{milkshakes} + 5 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \geq 14$
  - $1 \times \text{oranges} + 5 \times \text{chicken drumsticks} \leq 52$
  - $1 \times \text{oranges} + 5 \times \text{slices of pizza} \leq 73$
  - $4 \times \text{milkshakes} + 5 \times \text{slices of pizza} \leq 78$
  - $4 \times \text{milkshakes} + 5 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 54$
  - $4 \times \text{milkshakes} + 1 \times \text{oranges} + 5 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 54$

- Calcium constraints:
  - $3 \times \text{milkshakes} + 5 \times \text{oranges} + 3 \times \text{slices of pizza} + 4 \times \text{chicken drumsticks} \leq 79$
  - $5 \times \text{oranges} + 3 \times \text{slices of pizza} \leq 61$
  - $3 \times \text{milkshakes} + 4 \times \text{chicken drumsticks} \leq 78$
  - $3 \times \text{milkshakes} + 3 \times \text{slices of pizza} \leq 38$
  - $3 \times \text{milkshakes} + 5 \times \text{oranges} \leq 61$
  - $3 \times \text{milkshakes} + 5 \times \text{oranges} + 3 \times \text{slices of pizza} + 4 \times \text{chicken drumsticks} \leq 61$

- Iron constraints:
  - $2 \times \text{milkshakes} + 1 \times \text{oranges} + 2 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 70$
  - $1 \times \text{oranges} + 5 \times \text{chicken drumsticks} \geq 15$
  - $2 \times \text{milkshakes} + 2 \times \text{slices of pizza} \geq 6$
  - $2 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \geq 5$
  - $1 \times \text{oranges} + 2 \times \text{slices of pizza} \geq 8$
  - $2 \times \text{milkshakes} + 1 \times \text{oranges} \geq 12$
  - $2 \times \text{milkshakes} + 2 \times \text{slices of pizza} \leq 27$
  - $2 \times \text{milkshakes} + 1 \times \text{oranges} \leq 66$
  - $2 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 37$
  - $1 \times \text{oranges} + 2 \times \text{slices of pizza} \leq 59$
  - $1 \times \text{oranges} + 5 \times \text{chicken drumsticks} \leq 62$
  - $2 \times \text{milkshakes} + 1 \times \text{oranges} + 5 \times \text{chicken drumsticks} \leq 49$
  - $2 \times \text{milkshakes} + 2 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 40$
  - $2 \times \text{milkshakes} + 1 \times \text{oranges} + 2 \times \text{slices of pizza} + 5 \times \text{chicken drumsticks} \leq 40$

## 3: Implement the optimization problem using Gurobi
```python
import gurobi

def optimize():
    # Create a new model
    model = gurobi.Model()

    # Define the variables
    milkshakes = model.addVar(name="milkshakes", lb=-gurobi.GRB.INFINITY, ub=gurobi.GRB.INFINITY)
    oranges = model.addVar(name="oranges", lb=-gurobi.GRB.INFINITY, ub=gurobi.GRB.INFINITY)
    slices_of_pizza = model.addVar(name="slices of pizza", lb=-gurobi.GRB.INFINITY, ub=gurobi.GRB.INFINITY)
    chicken_drumsticks = model.addVar(name="chicken drumsticks", lb=-gurobi.GRB.INFINITY, ub=gurobi.GRB.INFINITY)

    # Define the objective function
    model.setObjective(6.35 * milkshakes + 7.44 * oranges + 2.49 * slices_of_pizza + 7.43 * chicken_drumsticks, gurobi.GRB.MAXIMIZE)

    # Add constraints
    # Protein constraints
    model.addConstr(4 * milkshakes + 1 * oranges + 5 * slices_of_pizza + 5 * chicken_drumsticks <= 90, name="protein_total")
    model.addConstr(4 * milkshakes + 5 * slices_of_pizza >= 8, name="protein_milkshakes_pizza")
    model.addConstr(1 * oranges + 5 * slices_of_pizza >= 10, name="protein_oranges_pizza")
    model.addConstr(5 * slices_of_pizza + 5 * chicken_drumsticks >= 20, name="protein_pizza_drumsticks")
    model.addConstr(4 * milkshakes + 5 * slices_of_pizza + 5 * chicken_drumsticks >= 14, name="protein_milkshakes_pizza_drumsticks")
    model.addConstr(1 * oranges + 5 * chicken_drumsticks <= 52, name="protein_oranges_drumsticks")
    model.addConstr(1 * oranges + 5 * slices_of_pizza <= 73, name="protein_oranges_pizza")
    model.addConstr(4 * milkshakes + 5 * slices_of_pizza <= 78, name="protein_milkshakes_pizza")
    model.addConstr(4 * milkshakes + 5 * slices_of_pizza + 5 * chicken_drumsticks <= 54, name="protein_milkshakes_pizza_drumsticks")
    model.addConstr(4 * milkshakes + 1 * oranges + 5 * slices_of_pizza + 5 * chicken_drumsticks <= 54, name="protein_total_max")

    # Calcium constraints
    model.addConstr(3 * milkshakes + 5 * oranges + 3 * slices_of_pizza + 4 * chicken_drumsticks <= 79, name="calcium_total")
    model.addConstr(5 * oranges + 3 * slices_of_pizza <= 61, name="calcium_oranges_pizza")
    model.addConstr(3 * milkshakes + 4 * chicken_drumsticks <= 78, name="calcium_milkshakes_drumsticks")
    model.addConstr(3 * milkshakes + 3 * slices_of_pizza <= 38, name="calcium_milkshakes_pizza")
    model.addConstr(3 * milkshakes + 5 * oranges <= 61, name="calcium_milkshakes_oranges")
    model.addConstr(3 * milkshakes + 5 * oranges + 3 * slices_of_pizza + 4 * chicken_drumsticks <= 61, name="calcium_total_max")

    # Iron constraints
    model.addConstr(2 * milkshakes + 1 * oranges + 2 * slices_of_pizza + 5 * chicken_drumsticks <= 70, name="iron_total")
    model.addConstr(1 * oranges + 5 * chicken_drumsticks >= 15, name="iron_oranges_drumsticks")
    model.addConstr(2 * milkshakes + 2 * slices_of_pizza >= 6, name="iron_milkshakes_pizza")
    model.addConstr(2 * slices_of_pizza + 5 * chicken_drumsticks >= 5, name="iron_pizza_drumsticks")
    model.addConstr(1 * oranges + 2 * slices_of_pizza >= 8, name="iron_oranges_pizza")
    model.addConstr(2 * milkshakes + 1 * oranges >= 12, name="iron_milkshakes_oranges")
    model.addConstr(2 * milkshakes + 2 * slices_of_pizza <= 27, name="iron_milkshakes_pizza")
    model.addConstr(2 * milkshakes + 1 * oranges <= 66, name="iron_milkshakes_oranges")
    model.addConstr(2 * slices_of_pizza + 5 * chicken_drumsticks <= 37, name="iron_pizza_drumsticks")
    model.addConstr(1 * oranges + 2 * slices_of_pizza <= 59, name="iron_oranges_pizza")
    model.addConstr(1 * oranges + 5 * chicken_drumsticks <= 62, name="iron_oranges_drumsticks")
    model.addConstr(2 * milkshakes + 1 * oranges + 5 * chicken_drumsticks <= 49, name="iron_milkshakes_oranges_drumsticks")
    model.addConstr(2 * milkshakes + 2 * slices_of_pizza + 5 * chicken_drumsticks <= 40, name="iron_milkshakes_pizza_drumsticks")
    model.addConstr(2 * milkshakes + 1 * oranges + 2 * slices_of_pizza + 5 * chicken_drumsticks <= 40, name="iron_total_max")

    # Optimize the model
    model.optimize()

    # Print the results
    if model.status == gurobi.GRB.OPTIMAL:
        print("Objective: ", model.objVal)
        print("Milkshakes: ", milkshakes.varValue)
        print("Oranges: ", oranges.varValue)
        print("Slices of Pizza: ", slices_of_pizza.varValue)
        print("Chicken Drumsticks: ", chicken_drumsticks.varValue)
    else:
        print("The model is infeasible.")

optimize()
```