it takes 3500 calories to equal one pound.
It all depends on the size of your onions. The world's heaviest onion was 16lb, 8½oz. 3-4 large onions would weigh about about a pound.
1 pound = 0.4 kg s
1/16 th. There are 16 ounces in a standard pound. Troy weight is different.
Choose a recipe that includes Sour Cream or Yogurt, and you will get a nice moist pound cake, banana bread, etc.