Food stimulus is a challenge so don't beat yourself up over that. I used to work in fast food and ate more than my salary's worth in food. If you feel cravings to eat, which is totally normal when food stimulus is present, try tea, coffee, or water. Black and green teas provide some natural appetite suppression. Make sure you are drinking lots of water throughout your fasting days from early on too.

It's also helpful to decrease carb intake when you are eating and get your nutrition from non-processed foods where possible (e.g. avocados, whole meats, eggs, nuts, veggies, berries, etc). Lowering your carbs and upping your fat intake will help your body get better at running on fat during fasts. This is an area I've struggled with in the past because of low fat brainwashing, but Jason Fung's books really made this click for me that fats are okay and helpful.