I know it is a provocative notion, but how many people have lost large amounts of weight and kept it off for a year or more just doing cycling? My own experience is, I get more out of riding as a social and a leisure activity when my weight is down, but as exercise activities go, haven't lost much weight with cycling alone.
What has worked best for me in losing and maintaining weight loss is consistent food logging, 45 minutes to an hour at the gym 5 days a week, equal parts weights, moderate to high intensity cardio including spinning (50% to 75% higher intensity than I would typically do riding outdoors), and mat classes like yoga or pilates for core strength and flexibility. That is my off biking season regimen. During biking season this year, and in past years, I have biked 2 to 3 times per week, 2 to 4 hours per ride in stead of 45 minutes to an hour at the gym, then the gym 2 to 3 days per week on days I do not ride. I notice it is easier to lose and maintain weight doing just the gym, than doing a combination of the gym and biking.
The question is, why? Am I eating more before, during and after long bike rides than I would just going to the gym? moving around less after long rides? Is it that at the gym, I work a greater variety of muscles? Is it that biking is not weight bearing, where as most of my gym activities are?