how do I stop food item from increasing hunger incorrectly?

I'm trying to make a survival game and so far I'm on the food system part of it. I made an apple that increases your hunger by 5 but every time I use it, It keeps going to 105 no matter what percentage the hunger is at, then if you keep eating it, it just increases the hunger further.

Hunger decrease script

local player = game.Players.LocalPlayer
local character = player.Character
local humanoid = character:WaitForChild('Humanoid')

local hunger = script.Parent.HungerBar

while wait(.5) do
	if humanoid.Health > 0 then
		if hunger.Value > 0 then
			hunger.Value = hunger.Value - 1
		else
			humanoid:TakeDamage(5)
		end
		
		local fullHunger = 1
		local currHunger = hunger.Value / 100
	else
		hunger.Value = 100
	end
end

My best guess was to put something like "If value >= 100 then value = 100" (same with 0) but I didn't know where to put it, so it only broke the script.

Tool Script

local tool = script.Parent



function onEquip()
	tool.Equip:Play()
end

function onActivate()
	wait()
	local player = game.Players:GetPlayerFromCharacter(script.Parent.Parent).PlayerGui.Bars
	local hunger = player.Hunger.HungerBar
	local thirst = player.Thirst.ThirstBar
	tool.Apple_Bite:Play()
	hunger.Value = hunger.Value + 5
	tool:Destroy()
end

tool.Activated:Connect(onActivate)

tool.Equipped:Connect(onEquip)

Is there something I'm missing on the tool script? Some sort of changed event like for the gui text to record the value?