Hey there!
The first thing to keep in mind is that 90% of weight loss takes place in the kitchen, while maybe 10% takes place on the bike. To lose weight, you are going to want to focus on eating whole grains, fruits, veggies, unprocessed meats, etc. You need to control your intake by maintiaining a high quality source of calories in.
And then when you ride your bike, you can supplement that foundation with a source of “calories out”, by causing your body to burn more calories which helps you to maintain a calorie deficit.
So how much will 200 TSS help? Well it will help about as much as the calories you burn in that 200 TSS (as long as you don’t overeat as a response to exercize). By keeping your intensity low, you can help minimize the need to “properly fuel” your workouts, which will again help you with your calorie deficit.
I hope that helps, let me know if you have any more questions for me!
Another forum that may interest you is this one:
Cheers!