I think this is not true because when you move away from the earth,the gravitational pull on you decreases and eventually no force acts on you and you become weightless. This concept is true vice versa. When you move closer to the center of the earth,the gravitational pull increases and becomes maximum at the center.

If you are still not satisfied. Then consider Newtons law of gravitation which gives us a formula ;

F= (GMm)/r^2 where F is the force acting between on you, G is the Gravitational Constant, M is the Mass of the earth , m is mass of any body and r is the distance between that body and the center of the earth. This formula states that Force between that body and the earth is inversely proportional to the distance between them.

This means that if the distance between them decreases then the force between them increases. Therefore its proved that weight of a body is more inside the earth than on the surface.

If you are still not satisfied. Then consider Newtons law of gravitation which gives us a formula ;

F= (GMm)/r^2 where F is the force acting between on you, G is the Gravitational Constant, M is the Mass of the earth , m is mass of any body and r is the distance between that body and the center of the earth. This formula states that Force between that body and the earth is inversely proportional to the distance between them.

This means that if the distance between them decreases then the force between them increases. Therefore its proved that weight of a body is more inside the earth than on the surface.