To lose weight through fasting, the duration and method depend on your goals and how your body responds, but common effective approaches include:

• 12 to 14 hours daily fasting: This beginner-friendly window allows the body to start burning fat for energy by about 12 hours of fasting, as ketones are released into the bloodstream. For example, fasting from 7 p.m. to 7 a.m. includes overnight sleep and can promote weight loss without calorie restriction during eating periods

• 16/8 method: This involves fasting for 16 hours daily and eating during an 8-hour window. It is popular because it extends the overnight fast and may enhance fat burning and improve insulin sensitivity. Some people start with 14 hours and gradually increase to 16 hours

• 24-hour fasts or alternate-day fasting: More advanced methods include fasting for a full 24 hours once or twice a week or alternating fasting days with normal eating days. These can lead to greater calorie deficits but may be harder to sustain and are not recommended for everyone

• 48-hour fasts: Occasionally fasting for 48 hours may offer benefits like enhanced cell repair and weight loss but comes with risks such as hunger, dizziness, and fatigue. This longer fast should be done infrequently (1–2 times per month) and only after becoming accustomed to shorter fasts

Weight loss results vary based on fasting duration, calorie intake during eating windows, and individual factors. Typically, intermittent fasting leads to gradual weight loss, about half a pound to one pound per week, primarily by reducing calorie intake

. Longer fasts (5 to 20 days) can cause more rapid weight loss but may not be sustainable and carry risks

. In summary, starting with a 12- to 16-hour daily fast is generally recommended for weight loss, with longer fasts reserved for experienced individuals under supervision. Consistency and calorie control during eating periods are key to effective and safe weight loss through fasting.