I am 10-months post op, gastric bypass. How much I eat, depends on what I'm eating.
If I'm eating leafy greens, I can eat quite a lot. If I'm eating a drier meat, I can't eat much.
A typical salad for me would be one leaf of iceberg lettuce, 5 grape tomatoes, about 2-3 ounces of protein, and a little over a tablespoon of salad dressing.
If I'm eating a burger, it will usually be one 1/4 pound patty, served with a slice of cheese and condiments, on a fajita-sized low-carb tortilla. I generally eat about 3/4 of this.
My usual breakfast is 1 whole egg and two egg whites, scrambled with cheese. Sometimes I can eat the whole thing and sometimes I can't.
I have hungrier days and less-hungry days. I've learned that overeating is unpleasant. If I eat too fast, food gets stuck in my chest and hurts. And that cuts my meal short, which is annoying. Do I still eat too fast? Yes - especially when I've waited too long to eat and I'm hungry. When I eat slower, the meal is more satisfying.
With what I'm eating, I'm basically in maintenance mode. My weight bounces between 166 and 170. Though I haven't hit goal, Both my nutritionist and I are okay with where I'm at, right now.