Picky as to how?
The course of meals will be proteins, proteins and zero calorie beverages. To lose the most the fastest. Otherwise the reductions will be slower.
Meats, Eggs, Chicken, Fish, Pork, Cheeses. Read Labels - Watch not only calories but sodiums, carbs & hidden ingredients, such as Sugar Alcohols.
You'll cut out ALL WHITE Foods such as Potatoes, Breads, Flours, Rice, Pastas, etc.
NO Carbs as they will only make you crave more carbs within two hours of eating them.

And remember your Multivitamins.
And sip, sip, sip! One gallon is very good two gallons is best of zero calorie drinks. Fluids in help flush out the fats. Yes you'll be going a Lot!

Veggies such as green leafy ones will be allowed latter on, but right out it will be just proteins. No Green Beans and such.

A very good book to have on hand which most consider the Bible of WLS is - "Weight Loss Surgeries for Dummies"

If you think you may have trouble then start the Post-op lifestyle NOW. I did six months in advance as Dr.Rehnke suggested. Go to the zero calorie beverages now cutting out all carbonated drinks like sodas.

MOST people don't want those others to receive any weight loss surgeries MAINLY due to the fact that WE WILL lose weight. And besides our personality and motivational being will change to the betterment of ourselves.

That their not changing and thus are affraid of being left behind!