Marking smart decisions on eating habits by fasting.

“To achieve fasting, one must downregulate the sensation of hunger,” explains Clarkson. The feeling of hunger is triggered by the release of ghrelin, a hormone from the stomach, which stimulates the production of two other hormones, NPY and AgRP, in the hypothalamus.

While these hormones induce hunger, there are numerous others, often referred to as “satiety hormones,” that suppress it. Leptin, a key satiety hormone released by fat cells, inhibits ghrelin production, signaling to the body that there is sufficient fat for burning.

Ghrelin is considered a short-term hunger response, released when the stomach is empty and experiences less pressure. It can be somewhat overridden by drinking water. In contrast, leptin operates on a longer-term basis.

Clarkson notes, “Our hunger hormones are regulated by various factors, including genetics. If your stomach is not distended, the nerves attached to the stomach and digestive tract signal hunger.” Staying hydrated can ease early hunger pangs until the body adjusts, she adds. The initial weeks of fasting may be challenging, but adaptation occurs.

For most people, ketosis sets in 12-24 hours after eating. If the evening meal is consumed between 18:00 and 20:30, the fed state ends between 21:00 and 23:30, and ketosis may occur by 06:00 to 08:30 the next morning. However, snacking or sugary drinks extend the fed state, potentially preventing ketosis before the next meal.

Clarkson suggests making informed decisions, such as eating an hour earlier in the evening and avoiding snacking. This could help achieve ketosis by morning. Intermittent fasting, approached carefully, may support the body’s natural repair processes, particularly as autophagy declines with age. While it may not be the ideal weight loss strategy, it can be a beneficial addition to a balanced diet.