How Intermittent Fasting Works

Intermittent dieting, also known as intermittent fasting , helps you lose weight without the enormous, sometimes counterproductive, effort of fasting all day.

Of the various formulas with which it is applied, the most functional is the 16-8 : the day is divided into two parts. In the first (8 hours) you can have breakfast and lunch , in the second (16 hours) there is fasting.

Intermittent fasting doesn't have to be done every day, but just 2 to 5 days a week , without stressing your body.

Expected fasting

Intermittent fasting , also known as controlled fasting, allows you to lose weight without any particular sacrifices, but by creating a fasting period of 12, 14, or 16 hours (the most popular formula) after your last meal. Essentially, it involves extending your natural nighttime fast and having a regular breakfast and lunch . But what exactly does 6/18 intermittent fasting involve?

16/8 intermittent fasting, as mentioned before, is an eating method that alternates 16-hour fasting periods with 8-hour eating windows.

In this plan, everyone can choose a time slot during which to consume all their meals of the day , limiting their food and calorie intake to just 8 predetermined hours. The remaining 16 hours of the day are dedicated to fasting, during which they don't consume any food and limit their drinks to non-caloric ones , such as water , tea , herbal teas , and coffee without added sugar.

This fasting model is based on the idea of ​​extending the natural fasting hours that occur during sleep by extending them into part of the day.

Benefits

Intermittent fasting is n't just useful for weight loss. Many doctors recommend it as a preventative measure for serious conditions, including:

• Il diabetes
• Hypertension
• La cholesterol
• Le heart disease
• Le neurodegenerative diseases

In practice, it is a comprehensive prophylaxis of the organism that, if necessary, can also become an elixir of long life, always and only if carried out correctly.

How it works

The weight-loss benefits of intermittent fasting are linked to the secretion of GH , or somatotropin , known as a growth hormone. GH improves body composition, tones muscles, with an increase in muscle mass, and helps with weight loss as it promotes lipolysis , the natural process of disposing of and breaking down body fat.

Intermittent fasting can be organized with a certain flexibility based on the lifestyle habits of those who practice it . The important thing is to respect the time intervals. The intermittent diet plan is simple: 8 hours of eating , 16 hours of complete fasting.

In general, the preferred times are as follows:

• Do the breakfast between 7 and 9
• Il lunch between the 13 and the 15

From that moment on, the 16-hour fasting period begins . It's also important to remember that everyone, even based on the advice of a nutritionist or professional, can decide how many days a week to follow the intermittent fasting diet. Generally, the most common options favor a minimum of 2 and a maximum of 5 days a week.

Is it better to skip lunch or dinner?

How many kilos do you lose?

In recent years, intermittent fasting had also raised hopes for weight loss. But now a countermanding effort has been made, issued by a group of researchers from the Johns Hopkins University School of Medicine and published in the Journal of the American Heart Association.

The research highlighted, on a sample of 550 obese people and for 6 years , that no link was found with previous studies that suggested an improvement and regulation of metabolism with intermittent fasting.

What specifically was discovered? First, that meal timing was not associated with significant changes in weight over the six years. No time parameter affected the subjects' weight. Even total sleep duration was not associated with any change in weight. The only factor that clearly affected people's weight was "how much" and not "when . "

According to previous studies, it would be possible to lose between 3 and 7 percent of body weight in about a month . For example, a person weighing 80 kg could lose up to a maximum of 4-5 kg ​​in a month. However, the outcome is uncertain and numerous factors must be taken into account, including diet, the person's physical characteristics, and the possible presence of hormonal or metabolic disorders.

What do you eat?

During the 16-hour fast, you can't eat any solid food . You can only drink water and low-calorie, sugar-free beverages. Intermittent fasting also helps you stick to meal times (important for weight loss), avoid overeating, and meet your nutritional needs, at any age.

Intermittent fasting, however, requires a person to be in good physical condition , capable of withstanding a prolonged period—16 hours, to be precise—without food. Before starting, it's always advisable to consult a specialist to determine the most suitable solutions for each individual.

Anyone who decides to try this fast should choose foods that help them feel fuller for a longer period of time and that help them build muscle mass. Foods to choose from include:

• Chicken breast
• Turkey
• Tofu
• Blue fish
• Greek yogurt
• Crustaceans
• Fruit
• Vegetables (preferably the green leafy one)

Diet type 16-8

Let's imagine a person who decides to adopt 16/8 intermittent fasting to improve their lifestyle and better manage their daily calorie intake. Here's how they might structure a typical day:

Feeding window : 12:00 – 20:00

• 12:00 (Lunch): Start your feeding window with a balanced meal that may include a generous serving of vegetables, a lean protein source such as chicken breast, turkey, or legumes, and a serving of complex carbohydrates such as quinoa or sweet potatoes.
  • Ex. Bowl of Quinoa with mixed vegetables, ceci, and a condiment based on extra virgin olive oil and lemon.
• 16:00 (Snack): A mid-afternoon snack to maintain energy and support your metabolism until dinner. It could be a handful of nuts and a piece of fruit, or one greek yogurt with a handful of fresh berries.
• 20:00 (Price): The last meal of the day before starting the fasting period. Dinner can be light but nutritious, with a strong presence of vegetables. An example could be a vegetable omelette with artichokes, tomatoes and feta, accompanied by a slice of whole grain bread.

Fasting Period : 20:00 PM – 12:00 PM the next day

Umberto Veronesi and intermittent fasting

Intermittent fasting, as Umberto Veronesi argued, represents a dietary approach that alternates phases of caloric restriction with periods of normal eating , with the aim of promoting health benefits based on the belief that scheduled periods of fasting can:

• Improve hormonal regulation
• Reduce inflammation
• Stimulate cellular autophagy

thus helping to prevent chronic diseases , improve insulin sensitivity and potentially reduce the risk of developing some types of cancer.

During the diet, a Mediterranean diet is recommended , rich in plant-based foods, whole grains, legumes, and fish , while limiting the intake of refined sugars and saturated fats. This not only supports weight loss but also promotes overall health improvement, in line with the holistic approach to nutrition and wellness advocated by the late oncologist.

It is important to emphasize that, despite the potential benefits, the intermittent fasting diet should be adopted with caution and preferably under the guidance of a healthcare professional , especially for those with specific medical conditions.

Veronesi's approach emphasizes the importance of a balanced and sustainable diet , which considers food not only as a source of nourishment but also of pleasure, contributing to a comprehensive vision of well-being that integrates physical and mental health.

Intermittent fasting more effective

In the field of intermittent fasting, scientific studies and research have offered a variety of perspectives that go beyond the well-known 16/8 pattern, exploring the effects and effectiveness of different fasting patterns.

For example, the 5:2 diet , which involves five days of normal eating alternating with two days of significant calorie restriction (about 500–600 calories per day), has shown improvements in participants' health markers, such as reduced fasting glucose levels and decreased waist circumference . However, some find this alternation more challenging to manage than daily fasting.

Also of interest is alternate-day fasting , which involves a day of free eating followed by a day of complete or semi-fasting (about 500 calories). This regimen has demonstrated potential benefits in reducing body weight and improving lipid profiles, but its long-term sustainability and psychological effects remain a matter of debate among experts.

Interestingly, recent studies have begun to explore the impact of intermittent fasting on the gut microbiota , suggesting that altering feeding patterns could influence the diversity and function of gut microbial communities, with possible positive repercussions on metabolic and immune health.

Despite this, it's important to note that intermittent fasting may not be suitable for everyone . For example, patterns such as 24-hour fasting or alternate-day fasting may be less recommended for those with a history of eating disorders or who may have difficulty maintaining a balanced diet on non-fasting days.

The key is to find an approach that fits the individual's needs, goals, and life context, always with an eye to sustainability and long-term well-being.

Intermittent fasting and breast cancer

A recent American study has yielded interesting results on the relationship between intermittent fasting and breast cancer risk . Conducted on a sample of 2.400 women, the study demonstrated that extending the nightly fast to 16 hours significantly reduces the risk of breast cancer recurrence.

Long-term risks

Some scientific research raises questions about the long-term risks of intermittent fasting. For example, in March 2024, researchers Meng Chen and Victor Wenze Zhong of the Shanghai Jiao Tong University School of Medicine presented the results of a study conducted on 20 Americans. Based on the data collected, they demonstrated a correlation between the 8-16 intermittent fasting diet and an increased risk of cardiovascular disease. Among the causes are the stress the body is subjected to and increased blood pressure. Other studies highlight the possible side effects of intermittent fasting, especially in the first few days of fasting: fatigue, especially mental fatigue, difficulty concentrating, and sleep disturbances. Furthermore, with such a prolonged fast, one can arrive at mealtime feeling very hungry, thus counterproductive to the previous effort. Finally, intermittent fasting, which can trigger eating disorders, is not recommended for adolescents, pregnant women, and athletes.

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