It would seem to me that a gradual increase in caloric intake while avoiding highly processed calorie dense foods might be necessary to keep some or much of the weight off.
Strict diets are temporary. If you don’t change your habits the weight comes back. Eating healthy gets easier after a few month’s. Even for body builders eating is 90% of the task.
Have 6 egg omelette with only a yolk or two for breakfast every day. Chicken breast or fish with veggies every day for Lunch or quinoa. Noodles and chicken and Rx bar or fruit for snacks and you have only had 900 cals. with 1 meal to go.
Make it a life style. Only food to eat is good healthy food. Fast food tastes like grease when you are away from it for a while.