As much as it would be great if we could reset our tummy to the loss of hunger phase after surgery we can’t. You can reset your thinking and your head though it’s not easy.
Start by going back to tracking everything you eat and drink & maybe keep a second record of what you were feeling at the time you ate or drink to see if there are any specific emotions (boredom, frustration, anger, sadness, happiness, stress, etc.) driving you to eat or any events that occured or situations you were in (Friday morning tea at work, socialising, at the movies, a sporting game, holidays).
Identify things you ma have let slide: portion sizes, protein intake, food choices, fluid intake, snaking, etc. check your activity levels. Then make a change. Drop a snack or work on reducing your portion size. After a couple of weeks make another change or two like increase your activity, or increase your fluid intake or swap out some food choices to better ore nutrient dense lower calorie options. And so on. Gradual changes are much easier to adapt to and adopt and always seem more achieveable. Become more mindful about your eating. Are you eating because you need to eat (real hunger) or just want to eat (head hunger - associated with emotions, situations or events). Eat slowly to allow time for your full/had enough message to register (takes at least 20 minutes).
Slowly work your way back to how you were eating when you were first maintaining. You’ll get there. All the best.