“less salt, more bitter vegetables”
The kidney is vigorous in winter, and according to the Chinese Wuxing system (five phases/ five elements), the kidney’s related element is water and, in taste, is saltiness. For the heart, it is fire and bitterness. Therefore, too much salty food will overboost the already vigorous kidney and, at the same time, weaken the heart. To maintain the balance between kidney (water) and heart (fire) in winter, be light on the salt shaker and try more bitter veg, like celery and kale.
Otherwise, the dietary focus in winter is to increase energy intake to keep warm. For example lean meat, eggs, fish, milk and beans are good to keep up your energy.