Intermittent fasting has become one of the most popular practices in recent years, driven by its spread on social networks and by those looking to lose weight or improve their health. However, until recently very little was known about what really happens inside the body when a person stops consuming food for several days in a row. Recent research shed new light on this process.

The study that revealed profound changes in the body

Scientists at Queen Mary University of London carried out research, published in the journal Nature Metabolism, which analysed the effects of prolonged fasting on the human body. The study focused on 12 healthy people who agreed to undergo a water-only diet for seven full days, without eating any solid food or caloric drinks.

During that period, the researchers took blood samples before, during, and after fasting, with the goal of monitoring the behavior of about 3,000 proteins circulating in the bloodstream. The follow-up allowed a detailed observation of how the body responded to the total lack of food.

What happens in the body during prolonged fasting

One of the initial findings was that, between the second and third day without eating, the body began to modify its main source of energy. Instead of using glucose from food, the body began to draw on fat stores to maintain its vital functions. This metabolic change is known, but the study provided much more detailed information about what happens at the molecular level.

Over the course of the seven days, the scientists found that about one-third of the proteins tested showed significant changes. Among them were some linked to the structural support of neurons in the brain, as well as others related to different tissues and organs of the body.

This finding is especially relevant because it suggests that prolonged fasting is not simply an extension of the body’s initial response to lack of food, but activates a distinct and differentiated physiological state. In other words, after three days, the body enters a phase with its own specific characteristics.

Weight Loss and Potential Health Benefits

In terms of visible physical results, participants recorded an average loss of 5.7 kilograms during the fasting week. However, the authors of the study stressed that the most important data was not the amount of weight lost, but the biochemical transformations observed.

The researchers noted that the modifications detected could open up new lines of research into the role of fasting in the treatment of certain health conditions, such as inflammatory processes. This offers a promising outlook for the development of future therapies.

The director of the Queen Mary University Research Institute in Precision Health explained that, for the first time, it is possible to observe at a molecular level what happens throughout the body during a period of fasting. In addition, he stressed that when practiced safely, fasting can be an effective tool for weight loss, although the additional health benefits only manifest after three days of total calorie restriction, later than previously believed.

Important Precautions to Keep in Mind

Despite the encouraging results, the researchers themselves were clear in pointing out the limitations of the study. The sample consisted of just 12 healthy people, meaning the results cannot be generalized to the entire population. Each body responds differently, and what works for someone in good health can be dangerous for people with pre-existing medical conditions.

The scientists also clarified that, in many cases, fasting is not a viable option for patients already facing health problems. For that reason, they hope the findings will help to better understand the mechanisms behind the benefits of fasting and, based on that knowledge, develop accessible treatments that don’t require the patient to stop eating.

What is recommended before attempting an extended fast

While intermittent fasting and other forms of food restriction have gained popularity, it’s critical to keep a few points in mind before practicing them:

• Consult a healthcare professional before starting any restrictive diet, especially if you have medical conditions.
• Avoid extreme fasting without proper medical supervision.
• Remember that each organism is different and responds in a particular way.
• Do not confuse rapid weight loss with a real improvement in overall health.
• Consider alternative options, such as a balanced diet and regular exercise.

In short, the research from Queen Mary University provides valuable evidence on the effects of prolonged fasting, but it also reminds us of the importance of approaching these practices responsibly and knowledgeably. The human body is a complex system, and decisions about food should always be made with reliable information and, preferably, with professional guidance.