when we dont eat anything in which day the body gets into storing fat mode

Your body does not suddenly switch into “storing fat mode” on a specific day of not eating. In general, when you stop eating, insulin drops and the body starts using stored energy; after about 12 hours of fasting, fat burning typically begins to increase, and it can escalate over the next 16 to 24 hours.

What actually happens

• In the first several hours, your body uses the glucose from your last meals.
• After roughly 12 to 24 hours without food, glycogen stores get used up and fat use rises.

• “Starvation mode” is often exaggerated; a calorie deficit usually still leads to fat loss, not automatic fat storage.

Important nuance

If you eat very little for a long time, your metabolism may adapt somewhat, but that is different from your body “choosing” to store fat because you skipped meals. Also, fat gain is driven mainly by a repeated calorie surplus over time, not by one day of not eating.

Practical takeaway

If your goal is weight control, focus on overall weekly eating patterns, enough protein, and a sustainable calorie balance rather than worrying about a single fasting day. If you’re fasting for longer periods or have diabetes, a history of eating disorders, or are pregnant or breastfeeding, medical guidance matters.

TL;DR: There is no exact day when not eating makes the body start storing fat; in fact, fasting usually shifts the body toward using stored fat after about 12–24 hours, not storing more of it.