How to Connect User input to While Loop

I am making a code where the user is supposed to choose a meat to eat and then it randomly assigns other foods to go with it to complete a meal. The loop should show you what items you have and at the end of the loop should print out the total calorie value. I coded the whole program but when I prompt the user for a meat, it stops and doesn't go to the while loop. Here is the program:

import random

usermeal = []
meatcalories = 0
fruitcalories = 0
vegcalories = 0
desertcalories = 0

#defining a list of different foods...
meats = {"NY Strip": 300, "Shrimp": 100, "Lobster": 200, "Clams": 300, "Scallops": 200}
vegetables = {"Asparagus": 50, "Potato": 80, "Brocoli": 50, "Kale": 30, "Beans": 40}
fruits = {"Apple": 40, "Orange": 30, "Bananna":45, "Kiwi": 40, "Mango": 40}
deserts = {"Ice cream":300, "Brownie": 400, "Cookie": 200, "Chocolate":300, "Candy": 100}


print("We are going to make you a meal today. Each meal will have one item from each food category:")
print(meats)
print(vegetables)
print(fruits)
print(deserts)
print("Start by choosing one of the meats")
meatchoice = input("Please choose the meat that you want: ")


while len(usermeal) == 4:
    #prompt the user for their meat decision
    if meatchoice not in meats:
        print("Please choose a meat from the options!")
    meatchoice = input("Please choose the meat that you want: ")
    if meatchoice in meats:
        usermeal.append(meatchoice)
        meatcalories = meats.get(meatchoice)
        print("This is your meal so far", usermeal)

#randomly chooses a vegetable
    print("Now lets get the vegetable!")
    random_veg = random.choice(list(vegetables))
    print("The random vegetable is:", random_veg)
    usermeal.append(random_veg)
    vegcalories = vegetables.get(random_veg)
    print("This is your meal so far,", usermeal, "and its calorie count:", vegcalories)

#randomly chooses a fruit
    print("Now lets get the fruit!")
    random_fruit = random.choice(list(fruits))
    print("The random fruit is:", random_fruit)
    usermeal.append(random_fruit)
    fruitcalories = fruits.get(random_fruit)
    print("This is your meal so far,", usermeal, "and its calorie count:", fruitcalories)

#randomly chooses a desert
    print("Now lets get the desert!")
    random_desert = random.choice(list(deserts))
    print("The random desert is:", random_desert)
    usermeal.append(random_desert)
    desertcalories = deserts.get(random_desert)
    print("This is your meal so far,", usermeal, "and its calorie count:", desertcalories)

print("Now since we have all the foods, lets see how many calories it is")
totalcals = meatcalories + vegcalories + fruitcalories + desertcalories
print("Total Calorie Count: ", totalcals)

I'm not exactly sure what the problem is. I know its something really small. If anyone can point it out to me I'd really appreciate it. Show the change in code please. Thanks in advance!

Look at what the condition is for your while loop.

while len(usermeal) == 4:

Now before the while loop runs, run this and see what it outputs

print(len(usermeal))

The TL;DR is that your conditional to run the while loop isn't true when it comes across it so the loop never runs.