Do our body’s need sugar to survive ?

We don't need sugar to survive.  The only "sugar" that the first inhabitants of the earth had available was from fruits which were in season - the sugars in fruits are called fructose. Natural and not refined. .  They did gorge on those fruits, but they weren't essential to survival.  But they were plentiful.  The rest of the year they lived without that sugar.  

Refined sugar of today, which comes in many forms and all sorts of different names, is what causes diabetes 2 and many other health problems in the world, today. 

Are we talking just sugar or all carbs? We definitely don't need added sugar. We are actually much better off without it. For carbs in general I know for a fact we don't need many. Look at the Inuit. They don't eat many carbs. Do we need any carbs to survive? No I don't think so. Our bodies can use fat as energy can the body can turn protein into glucose for the brain. Its not ideal to eat zero carbs but we can survive on it. 

Sugar or carbohydrates provide the fastest source of energy to our bodies but luckily they are not the only source for energy. Protein and fats will do too that is why it is possible to survive with minimal sugars. I say minimal because humans need carbs, even just a little. If they continue to do a purely protein diet for a long time, their kidneys will develop problems and fail.

Sugar is poisonous.   Flat out fact and why the obesity pandemic. 

Fructose is the poisonous part, but the fiber in whole foods slows down the absorption and allows the liver to purge the toxins. 

Added sugars = NO FIBER = poisonous,  fattening and responsible for diabetes II,  most heart disease,  most IBS,  most acne,  most hypothyroidism,  the growth of anxiety and subsequently nationalism and Trump.

COVID-19 is evidentiary of sugar's effects on life.

USA = 28% COVID-19 deaths

USA = 4% of world's population. 

Your body does not need added sugar to your food it will harvest the sugar that it needs from the food that you eat but in strict answer to your question you die if your body cannot harvest sugar your body cannot exist without sugar harvested from your food. 

No, we don't. 

Otherwise diabetic people would die.

What would you do if you had low blood pressure