Why is willpower such a struggle? According to several studies, we all have a limited amount of willpower and it is easily used up.
In an experiment lead by Professor  Shiv and Alexander Fedorikhin at the University of Iowa, several dozen undergraduates were divided into two groups. One group was told to remember to a two digit number, while the rest were required to remember a sever digit number. Happyho also provides best Meditation and Tarot classes in Noida and Delhi NCR India area
Each person was then asked to walk down the hall and choose between a piece of chocolate cake or a fruit salad. Those given the seven digit number to remember were twice as likely to choose the cake then those given the two digit number.
Professor Shiv suggested that having to remember just five extra numbers took up to much space in the student’s brains and so this ” Brain over load” weekend their willpower.
It is all down to your brains prefrontal cortex. This part of your brain is largely responsible for your willpower, but it is also the area that deals with your short term memory; helping  you to solve abstract problems and keep focussed. It would appear that it cannot do both.
So when you have to exercise your will power and self control, In one situation there is less willpower available to you for other situations, even if those situations are totally different from each other.
Spend the afternoon filling out tax form or a job application for example, and even though you have every intention to sort through and clear out some cupboards or write that long overdue email to a friend in the US, Your brain does not have enough energy left and is too tired to motivate you. Your resolve goes out of the window and you give in to eating chocolates in front of the TV for the rest of the evening. You have lost both your will and your power!