Intermittent Fasting – A Scientific Approach to Weight Control Through Fasting
We eat more than ever before and move less and less. Today, food is everywhere, available in countless forms and attractive packages, far beyond the purpose of ensuring survival. Food is no longer consumed solely to satisfy hunger, but also out of craving, boredom, habit, or inertia. Alongside other environmental factors, this reality has led us to an undeniable outcome: excess weight and declining health.
Intermittent Fasting – A Scientific Approach to Weight Control Through Fasting
According to the World Health Organization, in 2022, 1 in 8 people worldwide was obese.
Globally, since 1990, the number of obese adults has doubled, while the number of obese adolescents has increased fourfold.
In 2022, 2.5 billion adults (aged 18 and over) were overweight, of whom 890 million were obese.
In 2022, there were 37 million overweight children under the age of 5 worldwide.
More than 390 million children and adolescents aged 5–19 were overweight, including 160 million living with obesity.
In this context, interest in new and effective approaches to weight control has grown significantly. One such approach, increasingly popular in recent years for improving health and metabolic rate, is intermittent fasting. Restricting solid or liquid food intake to a specific time window, most commonly the 16/8 intermittent fasting method (8 hours of eating followed by 16 hours of fasting), leads to weight loss and positive outcomes in terms of dyslipidemia and blood pressure.
Contents
What is intermittent fasting?
Intermittent fasting vs. caloric deficit
How much weight can I lose with intermittent fasting?
Intermittent fasting meal plan
Intermittent fasting and health
What Is Intermittent Fasting?
Intermittent fasting is an umbrella term that refers to eating patterns that alternate periods of fasting with periods of food consumption. The term intermittent comes from the fact that it includes dietary models in which a person spends extended periods without eating or with very limited food intake, interspersed with periods of normal eating.
This cycle of eating interruption and resumption helps regulate insulin levels, mobilize fat stores, and support metabolic processes such as autophagy, which contributes to cellular health.
Intermittent fasting does not only support weight loss, but also:
Slows aging by helping reduce chronic inflammation associated with aging
Stimulates the biological process through which cells eliminate damaged components, facilitating cellular regeneration
Improves cellular response to insulin, the hormone that regulates blood glucose levels, maintaining stable glycemia, preventing type 2 diabetes, and supporting inflammation reduction
Reduces oxidative stress caused by free radicals, which can accelerate the aging process
Intermittent Fasting vs. Caloric Deficit
A caloric deficit refers to reducing the total number of calories consumed per day, with the important condition that caloric intake should not lead to malnutrition.
Studies show that in the short term (around 6 months), caloric restriction in overweight individuals leads to improvements in several cardiovascular risk factors, insulin sensitivity, and mitochondrial activity and efficiency. Mitochondria, often referred to as the power plants of the cell, play a fundamental role in producing the chemical energy needed to sustain all vital processes. They are also involved in regulating cellular metabolism, eliminating damaged cells, controlling oxidative stress, and maintaining ionic balance. As we age, both mitochondrial quality and quantity naturally decline.
Therefore, reducing daily caloric intake has effects not only on excess body weight but also on overall health, offering benefits in cardiovascular protection, improved mitochondrial function, and increased insulin sensitivity. This helps prevent or manage insulin resistance, a condition associated with type 2 diabetes and other metabolic disorders.
Intermittent fasting refers to extending the period of time during which you do not eat and can be considered an alternative to caloric restriction.
Although fasting can also lead to reduced caloric intake due to the elimination of meals over several hours (16 or 18 hours out of 24, depending on the chosen fasting protocol), the underlying mechanisms differ. In caloric deficit, the body receives fewer calories than it consumes, forcing it to use fat reserves to meet energy needs. This results in weight loss and metabolic improvements through reduced body fat. In intermittent fasting, insulin levels drop significantly, allowing the body easier access to fat stores for energy. In addition, intermittent fasting activates other biological processes, such as autophagy and hormonal regulation, which may provide additional health benefits beyond weight loss alone.
How Much Weight Can I Lose With Intermittent Fasting?
There is no universal answer to the question “how much weight can you lose with intermittent fasting?” The number of kilograms lost depends on several factors:
The duration of intermittent fasting
The type of intermittent fasting practiced, with the most popular being the 16-hour fast and 8-hour eating window
The quality of foods consumed during the eating window, as nutrient-dense, healthy foods lead to better results
Individual metabolic rate
Level of daily physical activity
According to studies, average results show a weight loss of 2–5 kg in the first month, while long-term healthy weight loss is approximately 0.5–1 kg per week.
It is also important to note that intermittent fasting is not suitable for everyone. Especially for individuals with chronic conditions or specific medical issues, consulting a physician before starting intermittent fasting is strongly recommended.
Intermittent Fasting Meal Plan
Intermittent fasting is a tool for weight control and health maintenance, not a miracle diet for rapid weight loss. There is not just one intermittent fasting method, but several fasting approaches, including:
16/8 intermittent fasting, the most popular and accessible method, involving 16 hours of fasting and an 8-hour eating window. The timing of the eating window can influence effectiveness. Studies support eating earlier in the day, suggesting beneficial intervals such as 8:00–16:00 or 10:00–18:00.
18/6 intermittent fasting, similar to the above, but with an 18-hour fasting period and a 6-hour eating window.
The 5:2 method, which involves normal eating 5 days per week and severe calorie restriction on the remaining 2 days, to about 500–600 calories per day.
Alternate-day fasting, alternating complete fasting days with normal eating days. On fasting days, a very low caloric intake (approximately 25% of daily needs, around 500–700 calories) is typically allowed, although some individuals choose water-only fasting.
24-hour fasting cycles, alternating one day of normal eating with one day of fasting.
Intermittent Fasting and Health
Weight control and health are deeply interconnected. Scientific literature, based on decades of studies and evidence, shows that maintaining a normal body weight is essential for preventing medical conditions such as metabolic syndrome and chronic diseases including type 2 diabetes, cardiovascular disease, hypertension, and certain types of cancer.
Although it may seem like a modern approach to weight control, fasting in various forms has been used therapeutically since ancient times.
Hippocrates, one of the most renowned founders of medicine, often referred to as the “father of medicine,” believed that food itself is a remedy. He argued that many diseases were caused by “self-intoxication” and that extending periods without food allowed the digestive organs and the body to recover. Fasting has been one of the most widespread traditions worldwide, practiced across cultures for religious, therapeutic, or cultural reasons. Used as a healing method, fasting was also seen by the ancient Greeks as a way to enhance cognitive abilities.
Philip Paracelsus, a pioneer in toxicology, stated that fasting is the best remedy, calling it “the physician within.”
Returning to modern times, preclinical and clinical studies have shown that intermittent fasting provides significant improvements in a wide range of conditions, including obesity, type 2 diabetes, and hypertension, while also contributing to better cardiovascular risk profiles.
