Whether or not fasting is bad for a kidney infection depends on several factors, including:

Severity of the infection: For mild infections, short-term fasting (less than 24 hours) is generally not considered harmful. However, for severe infections, fasting can be dangerous and could lead to dehydration, electrolyte imbalances, and even worsen the infection.

Your overall health: If you have any underlying health conditions, especially those affecting your kidneys, fasting can be risky. It's crucial to consult your doctor before starting any type of fast.

Type of fasting: Different types of fasting have varying impacts. Complete water fasting, where you consume no food or water, is generally not recommended for anyone with a kidney infection. Intermittent fasting, with specific eating windows, might be possible under medical supervision for mild cases.

Hydration: Regardless of the type of fast, staying adequately hydrated is crucial during a kidney infection. Dehydration can worsen the infection and put additional strain on your kidneys.

It's important to remember that I am not a medical professional and cannot provide medical advice.

Here's what I recommend:

1. Do not attempt to fast without consulting your doctor. They can assess the severity of your infection, your overall health, and advise on whether fasting is safe for you.
2. If you have a kidney infection, it's important to focus on staying hydrated and consuming a healthy diet as advised by your doctor. This will help your body fight the infection and recover properly.
3. Be aware of any worsening symptoms during a fast, such as increased pain, fever, fatigue, or changes in urination. If you experience any of these, stop fasting and seek immediate medical attention.

Remember, your health is paramount. Always prioritize seeking professional medical advice for any concerns related to kidney infections and fasting.