Intermittent fasting and hormones: benefit or harm
Intermittent fasting has gained significant popularity over the past few years among those seeking to improve their health or lose excess weight. This dietary approach alternates periods of eating with periods of fasting. The most common schedules include the 16/8 method (16 hours of fasting and 8 hours of eating) or the 5/2 method (five days of regular eating and two days of restricted calorie intake).
However, the question of how intermittent fasting affects hormonal balance is of great interest. Hormones are key regulators that influence appetite, metabolism, energy levels, and even mood. Let’s explore the hormonal changes that occur during intermittent fasting and whether it is beneficial for health.
How intermittent fasting affects hormones
1. Insulin and sensitivity for it
Insulin is a hormone that regulates blood glucose levels. When we eat, insulin levels rise to help the body store glucose for future use. During fasting, insulin levels naturally decrease, allowing the body to use fat stores as an energy source.
Studies have shown that intermittent fasting can improve cellular sensitivity to insulin, which is an important factor in preventing conditions such as metabolic syndrome and type 2 diabetes. However, individuals with existing blood sugar issues (e.g., hypoglycaemia) should consult a doctor before starting this practice.
2. Cortisol – the stress hormone
During prolonged fasting, cortisol levels may increase. This hormone stimulates glucose release from the liver, providing energy in food-deficient conditions.
However, persistently elevated cortisol levels can lead to negative effects, including poor sleep quality, anxiety, and an increased risk of chronic diseases. It is essential to avoid excessive stress and choose a fasting regimen that does not cause physical or psychological discomfort.
3. Growth hormone (HGH)
Growth hormone is one of the most important regulators of metabolism and tissue regeneration. During fasting, the level of this hormone can significantly increase—sometimes by up to five times.
An increase in growth hormone promotes fat burning, muscle preservation, and cell recovery. This is one reason why intermittent fasting has become popular among athletes and those looking to improve physical fitness.
4. Leptinand ghrelin– hunger and satiety hormones
Leptin signals the brain about satiety, while ghrelin stimulates appetite. Studies indicate that short-term fasting can lower leptin levels and raise ghrelin levels.
This mechanism explains why many people experience strong hunger when starting intermittent fasting. However, over time, the body adapts, and hormonal balance stabilises, making appetite easier to control.
Benefits of intermittent fasting for hormonal health
- Improved metabolism: Lower insulin levels and increased growth hormone enhance fat-burning processes.
- Appetite control: Over time, the balance of leptin and ghrelin reduces overeating.
- Reduced risk of chronic diseases: Regulating insulin levels and reducing inflammation can lower the risk of diabetes, cardiovascular diseases, and obesity.
- Improved brain function: Fasting stimulates the production of brain-derived neurotrophic factor (BDNF), which supports neuronal health and improves memory.
Potential risks of intermittent fasting
Despite its many benefits, intermittent fasting is not suitable for everyone. Some individuals may face the following side effects:
- Hormonal imbalances in women: Prolonged fasting can negatively affect oestrogen and progesterone production, potentially disrupting the menstrual cycle.
- Increased stress: Elevated cortisol levels may lead to emotional fluctuations and anxiety.
- Sleep disturbances: Evening fasting can make it difficult for some individuals to fall asleep.
- Risks for those with certain conditions: For example, intermittent fasting may be unsafe for individuals with type 1 diabetes, chronic gastrointestinal disorders, or eating disorders.
How to make intermittent fasting safe
- Consult a doctor: Seek medical advice before changing your eating habits, especially if you have chronic conditions.
- Choose an appropriate schedule: Start with gentler options like the 12/12 method (12 hours of fasting and 12 hours of eating) to allow your body to adapt.
- Listen to your body: If you experience significant discomfort, consider shortening the fasting period or returning to a regular eating pattern.
- Focus on food quality: During eating periods, prioritise balanced nutrition rich in proteins, healthy fats, and complex carbohydrates.
Remember, every body is unique. Before starting intermittent fasting, it is crucial to consult specialists. At the Clinical Dietology Centre of Dr. Bezugla, experts can help you select an optimal eating plan tailored to your needs and health.