Avoid processed foods and salty foods as much as possible during winters, as these foods can be harmful to kidney health. Eating too much salt increases calcium in the urine. It can lead to kidney stone formation, so try to eat seasonal green vegetables, fruits, fresh food, home cooked food and light food during this season. Limit intake of oxalate-rich foods such as spinach, beets, chocolate and tea, as excess intake can stress the kidneys. Instead, eat fruits and vegetables, pulses and a balanced diet, which promote kidney health.