Hi
mrc123,
My names Fred, nice to meet you.
To answer your question the best I can, it is possible that you will put the weight back on and maybe more.
So the reason some people get good initial results from a low-calorie diet is because your body shifts to fat for its main fuel source.
On a low-calorie, diet the body goes into survival mode. When the fuel source (fat) begins to get low, the body has a clever way of then slowing your metabolism down because it thinks food is scarce and doesn't want you to starve. However, with this, the body also tells itself that because there is no food we need you to go and get some. That means it increases appetite. So in other words, your body responds to a low-calorie diet by slowing down your metabolism and increasing your appetite. It is a survival tactic.
The reason people gain it back is because the more times people use this tactic the more your body becomes wise to it. Every time it senses a low-calorie diet coming it stores a little bit more fat away just in case it has to get through it again. The body is smart!! This process is called leptin resistance.
What I would try to do is:
Step 1: Take a look at what you actually put into your body in terms of food quality. Create a journal.
Step 2: Don't worry too much about calories as sometimes that can be irrelevant. (I can explain more on this if you want)
Step 3: Find an eating plan that works well for you. I personally have tried both the keto diet and the paleo diet and both have worked great for me.
Step 4: Understand that weight control is a lifestyle choice that has to be habitual. What your thinking about trying to do is great but long term what is going to benefit you more.
In 2015, I put on quite a bit of weight. At the time I think I was hovering around the 90kg mark. I decided to make a lifestyle change, stopped eating out as much as I was doing and cut back on the drinking. I did a 10-day transformation to cleanse my body of toxins (went down to 79kg) then approached the paleo eating plan so that I could keep up with eating healthy. I now try to live by the 80/20 rule. 80% of what I consume is healthy and 20% are food that I love but wouldn't consider healthy.
Hope this helps, if you need more help please feel free to ask.
Fred