Welcome to TE!! Great job making changes and starting the journey with cycling. I was a very serious cyclist for about 15 years, stayed trim, then after starting a family, stopped riding for a long time. In those years my weight crept up, went through an illness, and just this summer, actually right at 2 months ago, I started riding again. February to June, I walked and rode my stationary bike. Lost a little weight, but gained a fair amount of fitness. I got back into riding longer distances fairly quickly and have worked up to an OK average speed and better than average miles. These past several weeks, I have averaged about 150 - 180 miles a week and spend anywhere from 9 - 11 hours in the saddle. I've changed my diet a little bit, but not radically, as I know it's not a change I can make permanently. I've lost 20 lbs. in the last two months, and I've seen the most loss as I've ridden longer, faster and more vigorously. Cycling is good for weight loss, but it is a sport that you can put a little or a lot of effort into. Unlike running, where there is no coasting. As your fitness improves, your weight loss will increase because you will be able to go longer and harder. I've lost 40 lbs. total in a little over 6 months and I have abou 25 - 30 to go.
So to answer your question... Yes, I've lost weight by cycling, but didn't see much result until I was riding more miles, more quickly. However, I have not dieted seriously and I've gained a lot of muscle and cardio-vascular health, too.
Best of luck and welcome to cycling!
The bicycle has done more for the emancipation of women than anything else in the world. ~ Susan B. Anthony