A man weighs 600 N on the equator, but when he moves to the pole he finds a slight increase in his weight. This is because:
Radius of the Earth is less at poles since it is not a perfect sphere
On the Earth, g = GMR2 and weight are the force due to gravity i.e., mg. Since the Earth is an imperfect sphere, its 'R' is smaller at poles than at equators. The value of 'g' increases at poles as 'g' is inversely proportional to 'R'. Hence, the weight of the body also increases.