Andy weighed 156 + 36 = <<156+36=192>>192 pounds after growing taller.
An eighth of his weight is 1/8 x 192 = <<1/8*192=24>>24 pounds.
Over the next 3 months, Andy lost 24 x 3 = <<24*3=72>>72 pounds.
He now weighs 192 - 72 = <<192-72=120>>120 pounds.
Andy weighs 156 - 120 = <<156-120=36>>36 pounds less than at the beginning of the year.
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