According to my nutritionist after you enter the Maintenance phase, your meals should consist of equal parts of protein, fats and carbs but always put protein first. Fats are important because they help to control hunger.
It is common to have some limited weight gain after weight loss surgery. They call it a 20 pound bounce. The important thing is not let go beyond this 20 pounds. Most times this weight gain is due to a poor choice of snacks. Snacks should be limited to primarily to whole food options: nuts, natural nut butters, fruits, veggies, boiled eggs, string cheese, yogurt with berries and almonds, tuna pouches. Avoid processed packaged foods as much as possible.
Also do not expect to lose weight at a rate similar to right after surgery. Generally if you gained the additional weight over a couple years, then it may take a couple years of watching what you eat to get back down.