Moderation is the key to health. For example, sunbathing can help synthesis of vitamin D in the body, but excessive sunbathing increases the risk of skin cancer. Resistance exercise can help increase muscle mass, but excessive exercise causes muscle strain. These excesses have one thing in common: the harm they cause is not on the same metric as the benefit brought about by the moderate use. For example, too much sun exposure will not actually reduce the synthesis of vitamin D. Excessive resistance exercise itself will not lead to muscle atrophy.
So, are there behaviors or food intakes where overdoing creates the opposite result on the same metric as doing it in moderation? Here is an example:
Can Eating Mangoes Reduce Women’s Facial Wrinkles? Pilot Study Shows Promising Results
A 2020 randomized clinical trial at the University of California, Davis, found that eating 85 grams of mango per day can reduce facial wrinkles, but eating 250 grams can increase wrinkles. The experiment described in the research article is simple and was well done. As for why increasing the intake of mango several times will cause increase in wrinkles, the researchers can only guess: It may be related to the large amount of sugar contained in mango. This guess is not very convincing, but there is currently no better explanation. The paper has been cited in other articles over the past two years, but the test was not further studied by any other team.
The above test only examines one indicator: the amount of facial wrinkles. Moderate intake and excessive intake of mangoes produce opposite results on the same indicator. It is not that excessive intake causes some damage unrelated to the indicator, nor is it that large intakes reduce the amount of wrinkles more, or reach a peak (i.e. Mango intake is no longer associated with wrinkle reduction). I don’t know if there is a special term for this type of test results in epidemiology, but it is certain that such test results are not common.
