Has anyone tried to put a sack of sand sa pick-up bed nila? How many kilos?

Last night kasi, I brought home a sack of rice but I placed it sa rear passenger seat instead of the pickup bed coz medyo cautious ako baka mabasa ng ulan. I noticed the difference in the ride and manuverability ng pickup. Here are the changes:

Ride without sack of rice: Was bouncy before specially sa humps and lubak.
Ride with sack of rice: Its like my pickup was glued to the road. The bounce was lessened and the steering vibrations (specially when I accidentally drive over potholes) were minimized.

Manuverability with SOR: Good cornering

Yun nga lang, medyo lalakas sa consumption ng diesel coz of the added weight.

Question ko lang to those who practice this,
Is there any negative effects if I do this permanently?
Is there a difference if I put the sack at my pickup bed (last night kasi nasa passenger seat sa rear)
How many kilos do you carry?
:confused: