Sure you like riding your bike. Brings back childhood memories; is a fun way to get around; great way to get exercise outside; perhaps you race yours. Chances are you didn't get into bike riding just to lose weight, but if that were to happen, that wouldn't be a terrible thing.
But for some, getting onto a bike to get more exercise or lose weight is exactly why they got into riding in the first place. Problem is, their quest for that goal is either ruined by diminishing returns or worse, gains. Like any mode of exercise, it's not enough to just get up and go. It requires just a little bit more to understand that the bike hasn't failed you; you just need to know how to use it to your advantage.
Here are a few time tips for successful weight loss on the bike:
1. Before you do anything else and expect results, you must be willing to make some changes, most definitely in the nutrition department. Unless you plan on riding the terrain of France for 3 weeks in July at race pace, you're never going to be able to go out to exercise on a poor, even so-so diet. Real change begins in the kitchen.
2. Commute when possible. It's hard in this day and age and it can be quite dangerous, but instead of finding excuses, find solutions. Live within a reasonable distance to your job? Got a favorite neighborhood coffee place? Pick up the Sunday paper? Ride there instead most if not every day.
3. Depending on the type of bike you have, hit the trails and unpaved surfaces as it requires more energy (calories) than rolling over smooth road/paths. Mountain biking alone can burn more than three times the amount of calories in an hour as compared to flat road riding.
4. Don't avoid the hills - hit 'em hard! Not too much rocket since here, but climbing hills is harder than riding on the flats and burns a lot more calories in the process. You don't need to climb Mt. Everest every time you go out but plan some routes where there are some "bumps" along the way and make it a goal to never walk up the hill but pedal up the hill.
5. Stop coasting and keep pedaling. It's nice every once in a while to enjoy a little downhill or tailwind, but focus on pedaling as much as possible regardless of the terrain. You'll burn more calories the more you're working, not total ride time or distance.
6. Spend some time building muscle in the gym. Muscle (lean tissue) burns more calories the more of it you have. Don't think bulking up muscles. Think stronger, more powerful muscles which will get a termendous boost from spending a little time working on their development off of the bike. Plus, you'll then be able to ride faster and harder benefitting the previous points.