How to mount four 6-wire 10V load cells on Arduino or Raspberry Pi?
If you use a load cell rated for 200kg full load, with an output of 2 mV/V, and a supply voltage of 5V, then your output voltage will be 10mV for a 200kg load or 5mV for a 100kg load. A change in the load of 2kg will cause a voltage change of 0.1mV.

If you are digitizing this with a perfect ADC using a reference voltage of 5V you need at least 16 bits of resolution to see such a change in voltage. This will not happen with an Arduino. The ADC on an Arduino has 10 bits of resolution, so it can see changes of about 5mV. And we haven't even talked about accuracy yet.

So, you need to provide a differential gain of at least 100X if you want to use an Arduino. Otherwise, you need to find a better ADC. You also need to make sure that your analog reference voltage for the ADC, and the excitation voltage for the load cells, is as stable and accurate as you want your measurements to be.