Can I substitute a whole meal with something very light without repercussions?

Long story short, I used to be fat until like 7 years ago, and after a little something happened to me, I convinced myself I'd lose weight. So I did lose weight by cutting off one of my daily meals completely. I have been eating only 2 meals (with an exception occasionally) and sometimes snacks since.
2 and a half years ago, I started working at my current workplace, and because I was a novice, I was doing all the heavy lifting and stuff. In less than 6 months, I lost over 20kg, measuring 73kg. And over time, I improved at work, and I don't do a lot of physical stuff at work. But since I eat only two meals, I didn't gain weight, until the pandemic started.
Iwas on a 28day pause in the spring, and because I didn't work, fat stuck onto me. I'm not fat, but I liked my body when I had 73kg. I am tall, well built, so even with 90kg I don't look that fat, but I get a case of man boobs, and even though I started working after 28 days, I'm not getting fatter, but I'm not getting thinner either.
So, I have problems losing weight in a way. I guess I spend as much as I ingest. So I decided to switch up diets, but I don't like avoiding foods that I really like, so for 10 days now, I have avoided dinner, and have only been eating lunch.
I feel OK, my intestines have emptied, and I noticed my belly go down, and I expect I will lose the boobies in around a month from now, but I kinda got worried about possible health concerns. I don't feel nauseous, I haven't lost any physical strength, I'm sleeping well. I eat a good sized lunch, so I have no problems avoiding dinner, although my stomach rumbles all morning, until I eat lunch.
So, I thought I'd maybe eat something very light like maybe watermelon, till they're available, and then switch to something else. Watermelon seems like a good replacement for a meal, but I wouldn't know.
Basically, I'm asking for opinions and advices, but I won't stopt diet for at least a month anyways, so feel free to say whatever you like.
Can I substitute a whole meal with something very light without repercussions?
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