Fall, as we know is the season of harvest, collecting grains, nuts and fruits after a Summer long growth. Leaves start to fall, growth is restrained during Fall. This is the season where Yang energy is changed into Yin energy. Yang energy is taken from outside elements, photo synthesis from sun rays and warm temperature. Physical representation of Yang energy is reaching outward, such as longer and more branches and leaves, flowers and fruits. Yin energy is accumulated excess Yang energy to put away, it's captured within. There is no physical representation of Yin energy since it's kept within. Or we can say, when the trees stop growing, it's the beginning of Yin energy takes over. Although the trees stop growing, the roots are still taking in nutrients, instead of growing outward, it's being collected within which is the resource of Yin energy during Fall when activity is still going at a much slower pace. This is a tell tail signs of Yin energy.
Humans also follow this collective step, subconsciously to most. This is reflected in eating and drinking habits, such as we crave for comfort foods, darker more oxidized teas (including aged teas) in Fall. Teas with these characteristics have mellowed out the strong Yang energy, hence does not conflict with the Yin energy that our body stage is in.
Our brain can command us to do anything we want regardless of our body needs, but our body will give you signs of disagreement. If ignored or not understood, it can cause harm to our health for long period of time without knowing. Most of us does not realize living against nature can cut your life short 5 to 10 years. We have the potential to live 140+ years, average is only 80+. Compare to 40ish a century years ago, our scientist and doctors proudly claim we have extended life span in the last 40 years. We truly underestimated the wisdom, power of our body and its coordination with nature.
I will say this again, find a tea that your stomach agrees with at any time of the day, month, season and mood. Listen to your body, it will tell you. Do not drink a tea just because the media says it's good for this and that, how much weight you'll loose in 30 days.
You may not know when does your body like what type of tea initially. Well, we all go through a learning period of a chosen project including learning our own body. Make a cup of tea and see how well your body likes it, if not, try another type and discard the previous one. It can do you more harm than you'll realize if you force yourself to ingest it. Because the body will have to gather much more energy to digest something it does not agree with and even more energy to eliminate it from your body. Some times it can be trapped in your body as toxins which can cause long term problems. It will take you more time and nutrient to replenish the wasted energy as well. What you gain is not worthy of what you lost as the old Chinese phrase say.