What is an extended period of time in this context? I happen to consume all my meals within seven hours every day and only drink water in between. Would that help?
(Not doing this for health reasons, it is just a habit.)
It concludes that all fasting lengths are beneficial, and are likely going to result in a) reduction in weight and waist circumference, b) beneficial effects on blood lipids, regulation of sugar and other blood-related parameters, including lower blood sugars and higher ketone body levels, c) an increase in physical and emotional well-being and absence of hunger, d) a high probability of decrease of pre-existing health-complaints, e) very limited chance of side-effects.
[1] https://journals.plos.org/plosone/article?id=10.1371/journal...
Around day 3 or day 4 of a water-only fast or (the potentially easier but still effective option of) of a fasting-mimicking diet fast.