Microbe prototype under Unity

// Update is called once per frame
   void Update () {
      GameObject[]sugars = GameObject.FindGameObjectsWithTag("Glucose");
      for (int i = 0;i<sugars.Length;i++){
      GameObject sugar = sugars[i];
         if ((GameObject.FindGameObjectWithTag("Player").transform.position-sugar.transform.position).magnitude>radiusSpawnRes){
            Destroy(sugar);
            nbrSugarInSoup--;
         }      }
      while(nbrSugarInSoup < nbrSugarToCreate)
      {
         CreateRes("Sugar");
      }
   }
         
   // Instantiate a glucose prefab on the map
   void CreateRes(string _resType)
   {
      GameObject _curGameObject;
      Vector3 _resPos = Vector3.zero;
      Vector3 _playerPos = GameObject.FindGameObjectWithTag("Player").transform.position;
      while(_resPos==Vector3.zero||Mathf.Sqrt((_resPos.x-_playerPos.x)*(_resPos.x-_playerPos.x)+(_resPos.z-_playerPos.z)*(_resPos.z-_playerPos.z))<radiusNoSpawnRes){
      _resPos = (Random.insideUnitSphere)*radiusSpawnRes;
      _resPos.x+= _playerPos.x;
      _resPos.z+= _playerPos.z;
      _resPos.y = resGlucose.transform.localScale.y/2;
      }
      _curGameObject = Instantiate(resGlucose, _resPos, Quaternion.identity) as GameObject;
      _curGameObject.tag="Glucose";
      nbrSugarInSoup++;
   }
}