I know of someone who lives off the grid who charts their menstrual cycle, their diet, their daily goals, the lunar cycle, etc. As for their diet, it was rather complex because they were charting not only foods, but what time of day they ate said food, what moods that followed, and all kinds of details. They were also very detailed in their menstrual cycle as a means of birth control and related to the food charting, trying to hone in on how they felt psychologically each day. Rather than taking meds, this was the hopeful remedy. They noticed that anxiety, low energy , or melancholy, followed eating certain foods, and then experimented with changing their diet and charting those changes. It all sounds like rudimentary stuff, but as she lived off the grid and was self-employed, it was one way she could both spend time and be creative as well as take charge of her own health. Her journals were so popular, as she shared her design and findings on social media, that she might publish a bullet journal layout as another income. I'd never heard of one before her, and when seeing how many things she was charting, resulting in actual helpful results, I was impressed with it all. She was/is a bit obsessive, but proof is in the pudding. It wasn't a fruitless endeavor.