1. I would have said from the inside out, but that's a bad metaphor. Even though it also applies to the spirit. First and foremost, your body and spirit are connected. I don't think of spirit as something metaphysical. I think the spirit is actually sum of the emotions of ALL nerves inside your body. We like to think that we only think with our brains, but there are many other clusters of nerves that are capable of memory. Have you ever felt belly pain when you were truly angry? That's because the intestines have a very high density of nerves. In some animals it has even evolved to a second brain. We also have a bunch of nerves where our muscles are thus muscle memory. I'm going off topic.
Anyway, the spirit is the sum of all signals from your body. Those signals depend on how these body parts feel. What kind of food you eat will greatly affect those body parts and thus the nerves, and thus the spirit. Good nutrition will literally keep you high spirited.
2. Again from my biological point of view. What keeps people happy and high spirited often has a history in our evolution. Think about what you would do right now if you lived 100,000 years ago? Probably walk outside, exploring the world, looking for food. It comes to no surprise that people who take a good walk every day generally feel better. Sunlight positively affects our psyche. So does the ability to see far into the distance that's why we love standing on top of places. Evolutionary being able to oversee a wide area meant that you could see predators ahead of time, it gives you peace of mind. Last but not least, the walking part. Humans are born as nomads, yet here we are sitting way too much. There are physiological mechanisms in all of us that have adapted to constant walking. As a human, you must walk, walk at your own pace, but walk. We are made for it. Look at old people. They don't struggle walking. They struggle to get up when they sat or lie down. Most people can walk until the day they die.
If it was God's intention to feed your spirit by going to church, listening to certain music or visiting a bible study group, don't you think he would have done it right away? Well, he didn't. While you can try to replenish using our man-made solutions, I just want to remind you he created a whole world for you. The open nature is your church, the sounds of the birds or the ocean are your music, and your senses are your study group. But, that's just my opinion. I gave both a try. From megachurch contemporary worship concerts to bible study. The only thing that stuck with me was reconnecting with nature by disconnecting from the man-made world. I guess it kinda helps that I was raised Seventh Day Adventist where I take one day a week to completely unplug and leave the house. I always come back more inspired, more creative and less worried.
tl:dr Disconnect from the man-made things. Reconnect with the nature inside of you and outside.
