meal_tracking.py

import csv

# Notice that we've added data as a parameter to our write_data function
def write_data(data, file_path='meals.json'):
    with open(file_path, 'w', newline='') as f:
        json.dump(data, f)

def read_data(file_path='meals.json'):
    with open(file_path) as f:
        new_data = json.load(f)
    return new_data

# Read the data from our file into a variable
meal_data = read_data()

# Add new data. However you usually do it, put here 
meal_data['dessert'] = 5

# Write the updated data back to the file
write_data(meal_data)