In spite of what you have been told, you were never born to be fat.  Whether you believe a loving God designed the human body, or it evolved over millions of years of natural selection, one thing is abundantly clear, obesity doesn't make sense. 

If our ancestors had packed on 30 to 40 pounds or more during times of abundance, they would have never survived.  Storing some energy for future needs in the form of fat was good. But continued weight gain with all of its inherant dangers to health and the ability to deal with a hostile world, would be of no benifit.  In fact it would have been deadly!