Areas › Your body › Food, caffeine and fuel
You cannot patent a plant, so there is little commercial reason to fund expensive trials of one. When you read that a herb has no evidence, that often means nobody paid to look rather than that somebody looked and found nothing.
Both halves of that need saying. No evidence is not proof of no effect, and it is also not permission to assume one. It leaves you with an open question, which is an uncomfortable but honest place to stand. Marketing tends to fill that gap with a confidence it has not earned, which is why the same sentence gets used to sell things.
Qur’an and Sunnah
From the fruits of date palms and grapes you take sweet juice and wholesome provisions (Quran 16:67). What grows is treated as worth thinking about, so an untested plant is an open question rather than a closed one.
وَمِن ثَمَرَٰتِ ٱلنَّخِيلِ وَٱلۡأَعۡنَٰبِ تَتَّخِذُونَ مِنۡهُ سَكَرࣰ ا وَرِزۡقًا حَسَنًاۚ إِنَّ فِي ذَٰلِكَ لَأٓيَةࣰ لِّقَوۡمࣲ يَعۡقِلُونَ
From the fruits of date palms and grapes you take sweet juice and wholesome provisions. There truly is a sign in this for people who use their reason
Qur’an 16:67read it in the library
Translation: M.A.S. Abdel Haleem, The Qur'an, Oxford University Press, 2004.
What the research says
Where research is thin, good reviewers say so plainly. A review of intermittent fasting and cognition is candid that most of the mechanistic evidence comes from animal work and that the human findings are preliminary. That is what an honest description of an understudied area sounds like, and it is neither an endorsement nor a dismissal.
Gudden J, Arias Vasquez A, Bloemendaal M. (2021). The Effects of Intermittent Fasting on Brain and Cognitive Function.. Nutrients doi
Strength of evidence: one line of research. A single study, or a theoretical account.
Why it works
Research follows funding and funding follows what can be owned, so the things nobody can own get studied least.
This one is still a draft. It is waiting on a scholar and a clinician to read it before it is published.
Near this one
A physical symptom is not a free floating fact. Read it next to what your life has actually held, the early parts included, and it often makes more sense than it does on its own.
Before settling on a purely psychological account of months of anxiety or broken sleep, it is worth having the ordinary bloods done. Low iron, low vitamin D or low magnesium can produce symptoms that look exactly like a mental health problem.
The same brand of sweets is often made with plant based colours in one country and artificial ones in another. If a company can make it without the dyes elsewhere, the dyes are not essential to the food.