Thousands of years ago, our ancestors They faced a very different reality from today: finding food was complex and storing it even more so. This created uncertainty about when the next opportunity to feed would be, forcing the body to adapt to long periods without food. This generated an evolutionary adaptation to the possibility of having to fast for unpredictable periods of time.
Intermittent fasting, a practice that has gained popularity in recent years as a method of weight loss, takes advantage of this natural adaptation. This form of fasting consists of limiting calories according to different schemes: from fasting several hours per day, to avoiding eating one or two days a week or month. A more correct variant and increasingly recommended is the call intake during restricted timewhich allows you to consume all the desired calories during a specific time window, preferably from 7 or 8 in the morning and for about 10 hours. In this way, we achieve synchronize meal times with those of our biological clockwe respect our evolutionary biology and improve health by allowing the body to function in alignment with its natural rhythms.
The benefits of this time restriction are notable. They include weight loss, thanks to the use of fat reserves as a source of energy instead of carbohydrates; increased insulin sensitivity which improves glucose metabolism; increased growth hormone; reduction of cellular inflammation; decreased blood pressure; and improvements in mood, among others.
In animal models, intake during a restricted time is also associated with cellular rejuvenation. This occurs thanks to the production of NAD (nicotinamide adenosine dinucleotide), which activates proteins called sirtuins 1 and 3. These proteins improve mitochondrial energy production, stimulate autophagy – a process that eliminates dysfunctional cells and toxic components -, repair DNA and activate FOXO gene pathways associated with longevity.
Multiple scientific studies support the benefits of starting the fasting period early in the afternoon, around 6 or 7 p.m., and preventing it from exceeding 2 p.m. However, work presented in 2024 suggested a possible increased cardiovascular risk in people who restricted their intake to a period of only 8 hours. Although this finding is interesting, the study authors did not know the reasons for this time choice, which could be related to pre-existing health problems in the participants.
So what is the approach to follow to achieve the healthiest diet? Beyond intermittent fasting, the essential thing is to avoid processed products, prioritize the components of the Mediterranean diet – vegetables, legumes, fruits, white meats, nuts, olive oil -, eat moderate portions and avoid eating food after 8 a.m. the night. These habits, along with an appropriate time window for eating, will significantly contribute to making a big difference in our health in the short and long term.
*- Neurologist, specialist in stroke and health and well-being.
by Conrado Estol