I lost 60 pounds in a year, with cycling as my only exercise. I rode about an hour a day, averaging probably a bit under 5 days a week.
However, I was also eating healthy at the same time. My focus was not on losing weight, but on being more healthy. For me that means a balanced daily meal plan, including meat every day, vegetables every day, grains every day, dairy every day, eggs every day, fruit every day, and also nuts, sweet potatoes, brown rice, and bread periodically but somewhat regularly. Also, no fast food or junk food, and very little processed food. For me, the #1 enemy is added sugar. I avoid it diligently, as it is everywhere.
I monitored my food with the "MyPlate" app, and targeted my sedentary calorie target of about 2,000 calories a day in, while I was burning an estimated 'moderately active' about 2,600 calories a day out. Here is a free calculator for calculating all of this:
Flexible Dieting Macro Calculator
The nutrition is important and you will not lose weight on any exercise if you ingest more food energy than you burn off. And there is no "diet" that will permanently immunize you from putting the weight back on, if you return to your previous, unhealthy habits. The key is to establish a new, permanent, healthy and smart nutrition and exercise paradigm for yourself, and do NOT just pursue this like a short-term fix. It will only last for the short term if you do it that way.