The number of calories to eat per day depends on the number of calories burned per day. For example, an adolescent boy requires far more of a calorie intake than an adult. This is because; young people burn more calories a day as their metabolism is high.
At the end of the tax year, you will get a form P60 which sets out the total amounts paid to you and deducted from you for the previous tax year. A tax year runs from 6 April one year to 5 April the following year.
This will result in a lower tax deduction or a tax refund through PAYE. However, if the repayment is due towards the end of the tax year and you have already received your final pay for that year, you may have to claim a refund directly from HMRC or wait for the P800 process to happen.