What is negative feedback homeostasis?
Essentially maintaining optimal living conditions for the body.
First I'll define a negative feedback loop. This is pretty much any process that goes towards a certain equilibrium. It may seem simple, but vacuuming the floor is a negative feedback loop because you're performing a process that goes towards cleanliness. Once the floor is clean, you stop vacuuming.
Now for the homeostasis part: When your body digests something like white bread or candy, it's pretty much absorbing pure glucose. The glucose enters your blood stream, which drives up your blood sugar levels. The negative feedback loop involves insulin, which is released in order to bring back your blood sugar to normal levels by telling cells to absorb glucose and store it in the form of glycogen. Once your blood sugar is back to normal, your body stops releasing insulin.
Now, you've just gotten up in the morning, and having had no food to eat, decide to work out. Your blood sugar is very low, and since your cells are sucking up energy, it's going to drop even lower. Your cells need food to eat, so your body uses a negative feedback using glucagon to tell your cells to break down glycogen to release glucose and allow cells to use it to give energy to your muscles. Once your blood sugar is back to normal, it stops the glucagon, so it's a negative feedback loop.
Summary: negative feedback homeostasis uses processes like sweating, shivering, fluctuations in heart beat, and many more to maintain homeostasis, which is essentially the optimal living conditions for your body like temperature, pH, sugar and salt content, etc.