1 Serron: This black hole, will it affect our weight? I don't want to gain weight!
2 Spanners: The gravitational force will be high, so yes, your weight as measured on a scale will go up. But your mass won't change.
3 Serron: What's the difference! I'll still be fat!
4 Paris: Well, the way I see it your mass is already clearly very high, but is it because you're dense, or merely incredibly thick?

No doubt you all know that weight is a force equal to mass multiplied by the local acceleration due to gravity. Although your mass is an intrinsic property of your body, its weight varies depending on where you are. On the Moon, you would weigh about one-sixth as much, as the gravity there is roughy a sixth of Earth's.

Additionally, the gravity of Earth varies by as much as 0.7%, depending on where you are. This can make a difference of about half a kilogram (or about a pound) as measured by a set of scales (assuming your mass is somewhere around 71 kilograms).^[1]

[1] Although you'd have to take the same scales with you. Scales are normally calibrated to read out mass units (kilograms) rather than force units. So a set of scales in one place is calibrated to read the force of your weight, and convert it back into mass units correctly, based on the local acceleration due to gravity. If you then went to a different location where the gravity was 0.7% less and stepped on a set of scales there, you'd get the same reading, because that set of scales will have been calibrated for the local gravity there. However if you took your original scales with you, they would read about a half a kilogram less.^[2]

[2] All of this assumes the scales are calibrated accurately enough that they can read to better than half a kilogram accuracy, of course.