Just go plant-based. Fasting is an eating protocol, not a diet.

Fasting for more than 3 days without medical supervision can have a disastrous effect on your health

• https://nutritionfacts.org/video/alternate-day-intermittent-fasting-put-to-the-test/
• https://nutritionfacts.org/video/is-alternate-day-intermittent-fasting-safe/
• https://nutritionfacts.org/video/does-intermittent-fasting-increase-human-life-expectancy/

You can verify the citations of the videos below them.