Is it beneficial to be taking in as much sunlight as possible while in a dry fast? How does it impact the fast? Should it be avoided?
As much as possible? No. Granted, your genetics (skin pigmentation), age, time of year, weather, and where you live on the planet are all factors in how much sun you should get optimally. Want to age yourself faster? Sunlight is still one of the best ways to do that. It’s one reason why our parents, grandparents, great grandparents looked so much older than us at the same ages. Kids played outside and teens/adults worked outside all day back then.
The amount of light on our skin needed for vitamin D is about 20-40 minutes at 75% exposure of our body (shirtless, pair of shorts) per day, and it’s better at around 11am-1:00pm, than later. There is an app DMinder that is free and helps tell you based on all these factors when you should sunbathe and for how long.
Vitamin D is definitely hands down important, and best gotten from the sun. I just wanted to give some caution for people who think then they should just spend 4 hours in the sun, especially dry fasting. If you burn your skin, you have just damaged your skin. If you are white like I am, you can burn in 40 minutes. Also, where I live, for 180 days of the year we don’t even get the type of sunlight that helps us make Vitamin D even if we are in the sun!
Side note, using mushrooms with the heads upside down on a pan and basking them in the sun for 2 days is one cheap and very effective vitamin D supplement.