Long-term fasting (such as more than 48 hours) is a healthy behavior that needs to be treated with caution. Although it may bring potential benefits (such as autophagy, metabolic regulation, etc.), there are also certain risks. The following is a step-by-step guide, but please be sure to consult a doctor before trying, especially if you have a chronic disease, pregnancy, a history of eating disorders, or a weak body. --- ###**1. Preparation before fasting** 1. **Health assessment** -Consult a doctor: check whether indicators such as blood sugar, blood pressure, and heart function are suitable for fasting. -Contraindications: patients with diabetes, patients with hypotension, people with eating disorders, pregnant/lactating women, etc. should be avoided. 2. **Psychology and goal setting** -Clear purpose: is it for health improvement, metabolism restart, or other reasons? Avoid trying to follow suit blindly. -First attempt: It is recommended to start with a shorter fast (such as intermittent fasting at 16:8), gradually extend it to 24 hours, and then transition to more than 48 hours. 3. **Diet adjustment (2-3 days before fasting)** -Reduce refined carbohydrates: reduce sugar intake and avoid severe fluctuations in blood sugar in the early stages of fasting. -Increase healthy fats and proteins: such as avocado, nuts, and fish to help stabilize energy. -Supplement electrolytes: Consume foods containing magnesium, potassium, and sodium (such as spinach, bananas, and sea salt) in advance to prevent electrolyte imbalances during fasting. --- ###**2. Implementation during fasting** 1. **Time selection** -It is recommended to avoid high-intensity work or exercise starting from non-working days. -For example: it starts after dinner on Friday and ends on Sunday night. 2. **Key precautions** -**Water supplement**: At least 2-3 liters of water per day, and a small amount of sea salt can be added (to avoid hyponatremia). -**Electrolyte management**: Drink sugar-free electrolyte water, or take supplements (magnesium, potassium tablets). -**Avoid strenuous exercise**: Light activity (walking, yoga) is enough to avoid hypoglycemia or dizziness. -**Monitor body signals**: If you experience panic, dizziness, or severe fatigue, stop immediately and seek medical attention. 3. **Possible stages** -12-24 hours: hunger is obvious, relying on willpower to overcome. -24-48 hours: The feeling of hunger decreases and may enter a ketogenic state (fat energy supply). -More than 48 hours: more stringent monitoring is required. Some people may experience dizziness and headache (signs of insufficient electrolytes). --- ###**3. Re-eating: more important than fasting** 1. **Principle** -Re-eating time ≥1/2 of the fasting time (for example, 48 hours of fasting, at least 24 hours of re-eating). -Start with easy-to-digest liquid food and gradually transition to solid food. 2. **Phased dietary recommendations** -**The first stage (the first 4-6 hours)**: Bone broth, coconut water, diluted apple vinegar (supplement minerals). -**The second stage (within 24 hours)**: Steamed vegetables, fermented foods (such as sugar-free yogurt), and a small amount of high-quality protein (such as eggs). -**The third stage (after 48 hours)**: Resume normal diet, but still need to avoid foods high in sugar and oil. --- ###**4. Potential risks and alternatives** 1. **Risk warning** -Hypoglycemia, muscle loss, temporary decline in immunity, menstrual disorders in women. -Long-term fasting may cause overeating or metabolic maladaptation. 2. **Safer alternative** -**Time-restricted eating (TRE)**: For example, the daily eating window is controlled at 6-8 hours. -**Improved fasting method**: 5:2 diet (only consume 500-600 kcal 2 days a week). --- ###**5. Resources and tools** -Monitoring tools: blood glucose meter, sphygmomanometer (especially necessary for diabetics). -Support the community: join a professionally guided fasting group to avoid blindly trying alone. --- **Finally emphasize**: Individual differences are great, and fasting is not a panacea. The foundation of health is a balanced diet, sleep and stress management. If you have any discomfort, please stop immediately and seek professional help.