Resistant starch isn't going to "impact" weight loss because it is starch, or resistant starch, or a carbohydrate, or anything like that per say. People gain weight when they "add in carbs" because they do exactly that - they ADD them. They take all their normal foods that they eat and dump on piles of carbohydrate. All that leads to is weight gain since you're adding hundreds of additional calories of food per day.
What you want to do is displace food calories for the resistant starch to see benefits. I would not recommend displacing protein sources. That would likely lead to fat gain since you'd be switching out a structure substrate that can't really be stored as fat (protein) for an energy substrate that can be stored as fat (carbohydrate). You want to displace fat for carbohydrate. If you want to add resistant starch to your diet, I would recommend cutting fat intake significantly - minimize fats and oils as much as possible at first, and if that isn't enough, experiment with leaner cuts of meat.
I consume resistant starch almost every day because I love cold potatoes. I make a big batch and toss them in the fridge, then put them in my lunch salads as needed. Funny thing - it's a fairly recent turn in the past 6 months. I've been simply ADDING them to my meals and not removing anything, and I haven't gained any weight at all. If anything, they help fuel my workouts so much better than rabbit food they may be helping me burn energy better.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.