Combining two functions into one?

How would I go about merging the deplete() function into the fuel() function where it calls for the deplete() function to run in line 6?

local fuelFull = true
local started = false

function fuel()
		if fuelFull == true and started == false then
			deplete()
			print 'STARTING DEPLETING'
		elseif fuelFull == false then
			print 'EMPTY'
		end
end

		
function deplete()
	started = true
	print 'DEPLETING'
	while true do
	script.Parent.FuelValue.Value = script.Parent.FuelValue.Value -1
	wait (.1)
	if script.Parent.FuelValue.Value <15 and script.Parent.FuelValue.Value >0 then
		print 'LOW FUEL'
	elseif script.Parent.FuelValue.Value >15 and script.Parent.FuelValue.Value >0 then
		print 'SAFE'
	elseif script.Parent.FuelValue.Value <15 and script.Parent.FuelValue.Value >-1 then
		print 'EMPTY'
		fuelFull = false
		started = false
	end
	end
end

script.Parent.Touched:connect(fuel) 

Try re-ordering when you declare functions. Declare the deplete function before declaring the fuel function.