People who actually can lose weight and keep it off, can win everything in life? How? Why?

What does it take to lose those stubborn extra weight that are making you unhealthy day by day? A well-planned routine and consistency seems like the more obvious answered, however it’s more than just those two things to be fair.

I think the bigger question for everyone to answer and understand is; Why is it easy to do these things at the start, but harder in the short term to be consistent fully?