Skip breakfast or dinner earlier to lose weight: the promise is making the rounds on social networks and podcasts. According to numerous viral contents, exceeding a certain time limit would allow you to tap directly into the dimples.
What really happens once you’re at the table? Let’s take a closer look at this mechanism, well known to specialists.
At 12 hours of fasting, the real metabolic shift
The principle is based on the management of glycogen, this reserve of sugar stored in the liver and muscles. Questioned by the Aufeminin site, the Spanish pharmacist Javier Fernández Ligero specifies “that after 12 hours of fasting, the body begins to deplete its glycogen stores as an energy source.
It is therefore not a question of increasing this stock, but of emptying it. When these liver reserves decrease, the body begins to draw on fatty acids to function. Muscle glycogen remains mobilized for physical effort. The more activity is sustained during this period, the more the decline in stocks accelerates.
From digestion to fat burning: the timeline
The chronology of a fast is organized into several distinct phases:
- From 0 to 4 hours: the body digests the last meal and stores sugar;
- From 4 to 12 hours: it draws on liver reserves to maintain blood sugar levels;
- From 12 p.m.: the body switches to priority use of fats.
Eating your last meal at 8 p.m. and eating at 8 a.m. the next day is enough to reach this threshold. To activate autophagy, this natural cellular recycling mechanism, the expert mentions a window of 14 to 16 hours. This practice improves insulin sensitivity and helps regulate food cravings.
Adopt the 12/12 rhythm safely
To start, the 12/12 formula remains the most accessible. It consists of spacing out dinner and the first meal of the day by 12 hours. Postponing breakfast two hours after waking up, by incorporating a gentle walk, helps to stimulate destocking without rushing the body.
Be careful though: this pace is not suitable for everyone. Pregnant or breastfeeding women, diabetics under treatment, or those with a history of eating disorders should seek medical advice before changing their habits. The priority remains to listen to your feelings without forcing.