Personally I stick to no dairy, no wheat/gluten and keep it simple and clean. For breakfast I eat pears and apples (as much as I need to feel comfortable), lunch is a salad with chicken breast of turkey breast, sometimes no dressing and if I do choose a dressing, I use a tiny amount. Snack is pears/apples (these are my "safe" fruits) and dinner is salmon or chicken with asparagus, or steamed carrots....no salt, no pepper, no butter.....keep it plain and simple while your gut heals. You might find that you can handle other fruits.....I can't do bananas......tried grapes today, those went ok. Take it slow with foods and keep a journal to see what works for you and what doesn't. Sweet potatoes work for me too, bake them and have a small salad with it. Try not to overwhelm yourself at the beginning.

I found an app called mySymptoms that is great for journaling.

I agree with SJH I eat a lot of salads with a meat chicken, salmon, tilapia, turkey meat and a lot of steamed vegetables, that is pretty much what I eat on a daily basis. I will try the pear and apple because I have never tried it but I have had an apple and banana and just water smoothie that works well with my system.

I agree the websites contradicts themselves totally. But then I see here the previous posts and I can't do a lot of the things other do. Like grapes? that kills my stomach. So you are going to have to learn on your own what you can eat and what you can't. Which is why gastritis lasts so long.

Salads - No for me. You can't do tomatoes. Raw vegetables or vegetables that are gassy (like asparagus) are no no's for me. Actually even when I didn't had gastritis I couldn't eat asparagus or brussel sprouts.

Here is my meal plan:

Breakfast
Cream of rice cereal - I use lactaid milk to cook it
Boiled eggs,
Bread - gluten is fine, I would be more careful with the gluten free ones because they have a gazillion ingredients. If anything has more than 3 ingredients chances are it will hurt. I buy baked fresh with few ingredients
Butter is fine. Butter is a easily digested fat, Eaten in moderation is perfectly fine. I put a bit olive oil and some butter and make scrambled eggs, eggs over easy and such with no ill effects at all.
Papaya - papaya is your friend, go buy it.

Lunch/Dinner

Carbohydrates:
Rice, rice , rice - rice is your friend. I know americans here don't eat it much but where I'm from that is eaten like potatoes, everyday and it's good for you safe for gastritis.
Pasta - okay with me too. I use thin spaguetti. Boil it and drizzle with olive oil. No ill effects from that.

Meats:
Chicken rotiserri is good. I buy it from any supermarket and never have ill effects.
Fish- any is good. I cooked it in pan with veggies (zuchini, squash, eggplant, mushrooms) in olive oil and some salt
Turkey/chicken ground meat

Sides:
potatoes- mashed/baked or boiled
sweet potatoes - mashed or baked
Okra
veggie medley - zuchinni, squash, mushrooms, eggplant
spagetti squash
yams
Southern Collard greens -really soothing for the stomach!
avocados -moderation
plantains - green or ripe

Drinks:
Rice milk
Fiji water - bottle/tap water can be acidic so stick to alkaline waters

No cheese! this is the hardest thing of this diet. No nuts. Nothing fried. No pizza! Sorry but this is depressive.

I forgot to mention about the chicken I do not eat the skin. Even with no gastritis I do not eat the skin, That is bad fats.

I used to go on a fresh, organic juice diet for a few days. My Gastro doctor told me it helped the stomach by not having to produce as much stomach acid to break down the food and give it a bit of a rest. I used mainly FODMAP vegies & fuit and this would ease the pain a bit. I the introduced soups & mashed foods for a few more days and this would help alot.

I do not agree with your gastro logic. The whole point is to block acid at least for ulcers/inflamation so that the stomach lining can heal. If I drink or eat anything acid I get real sick. Actually I got into this gastritis because of drinking orange juice and lemonade on the daily.

Now the soups and mashed food that is good.