This is how I had it explained to me.... Any sun contact causes a drain on the body and it's energy form or astral form etc. It causes Aging, loss of energy, grounding sensating, weakness, decrease of immune system etc. basically all of your components that make you up are sensitive to this drain on you and react. Many feel it as the hunger. Even just daily energy use can cause it without sun.
Here are some of the ways to recharge different energies that your body absorbs and can draw from.
-Natural energy vortex or high energy places with natural rock formation, water or nature.
-Any electric current that is active like a heating blanket, or heating pad. They are good to put on injuries to help them heal.
-Living plants like a garden spot especially at night. Yes sitting under a tree with your back against it helps.
-Flowing water sources like a stream, river or waterfall. I have been at waterfalls that felt wonderful.
-Crystals or gemstones can be used to store energy in till you need to absorb it to take the edge off.
-Live fresh raw foods can be used to regenerate the bodys cellular structure.
-Setting up an energy source where you live to create an energy field to live in. I have 1 inch quartz crystals inbedded one inch down in the yard around my house that are all pointed to a point above the house. Esp. at the cardinal points. People can feel it when they enter the yard. They cause a build up of energy within the house.
Alone they can only help a little but when combined they can help you over the rough times. I'm sure there are many other methods...Just remember the hunger is your body screaming at you and has to be taken care of. Try a few and see if it helps. I know if I stay out of the direct sun I can exist by these methods. Maybe it will work a little for you too.