Question....
I think they are basically the same. Focus on protein. 600-800 calories per day, 80g of protein, less than 40g of carbs, 100oz of water, 30-60 mins of exercise. There are probably some foods that you cannot eat that your niece can but I am not all that privy to the post-op diet for RNY and I do not recall from my research. I know there are certain medications that you cannot take that your niece can.
I would think you would approach fats a bit differently. I like to tell the people I counsel that they should be a bit higher than was docs and nuts recommend like in the 25-35g per day, especially for women. But I would think with RNY and bypassing some of the small intestine that fats would cause you some intestinal distress so I would guess the RNY diets probably need to be inherently low fat.
They are actually pretty different. Sleeve patients don't have the malabsorption and malnutrient qualities of the RNY. We absorb everything. Sleevers can get the slimies (or whatever they are called), but it's usually because we've eaten past what our stomachs hold.
The only vitamin we are required to take is B12. Most of us take more than that. I take a multi-vitamn iwth iron, calcium, B complex, Vitamin C - but I'm old-ish and need more vitamins.
Ibuprofen seems to be on the "whatever your doctor says" list. My doc says no ibuprofen, but my friend's doc is fine with it - as long as it is not overused.
Baby food is nasty, but if that is what her doctor says to eat, then she's doing the right thing. Most docs have different stages and many of them look like this: 1-2 post op liquids only - this can include very wet soups, 2-4 weeks post op mushies (very soft food), 4-6 weeks wet meats an soft veggies, after 6 weeks eat foods as they are tolerated.
The biggest thing with any of the surgeries is to know your capacity and not to test it it early on. Frisco calls it eating under your sleeve.
If I were you, I'd ask her how you can best support her. They are different surgeries. Let her teach you what works best for her.
You are very sweet to support her.
My father-in-law had the RNY gastric bypass, and I have the sleeve (we share our home with him).
While the concepts are the same, I noted he ate more and faster after the surgery than I have. After two years, he's back to eating as much as he did before, but the malnutritive element of the RNY has prevented him from gaining back weight.
I stayed on soft food much longer -- still on soft food, to be honest. I'm nervous about trying "real food" again. I have to eat slower because the sleeve is more restrictive than RNY.
The one frustration I have is he's always saying "After my surgery, I _______" and it's often in conflict with what I'm doing or I learned. He hasn't accepted my surgery is different than his, and I'm handling it different than he did. Having gone through the same education class as he did, I consistently see what he is doing that he shouldn't be. Whether it's from not paying attention, or just not wanting to change his ways.
Mind you... he did lose 100+ pounds and he's healthier. But he could have lost more if he hadn't repeated again and again "I can eat whatever I want..."