Prevent user from changing game values in the browser console

Any player can easily cheat on this game by changing the amount of cupcakes through the browser console. I wanted to know if there was a way to prevent the user from doing so. This is also posted on github.

var numberOfCupcakesDisplay = document.getElementById("numberOfCupcakes");
var cupcake = document.getElementById("cupcake");

function updateValues() {
    numberOfCupcakesDisplay.innerHTML = amountOfCupcakes.toString();
    //displays number of cupcakes to screen
    document.getElementById("amountOfToasters").innerHTML = amountOfToasters.toString();
    //displays number of toasters to screen
    document.getElementById("toasterButton").innerHTML = "&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp" + Math.round(costOfToasters).toString() + " cc";
    //changes cost of toaster every time it is bought by 110%
}

cupcake.addEventListener('webkitAnimationEnd', function(e){
    e.preventDefault();
    this.style.webkitAnimationName = '';
}, false);

function clickCupcake() {
    ++amountOfCupcakes;
    cupcake.style.animation = "shiftCupcake";
    cupcake.style.webkitAnimationName = "shiftCupcake";
}

updateValues();