Disclaimer: I am not in the medical profession but my comments are based on my observations from helping people get back on the bike the first time since childhood.
The following is a reaction to Translating Calorie Counts into Exercise Equivalents Leads to Healthier Choices in Scientific American.
So how long does it take to burn 250 calories by bike, 73 minutes or 17 minutes? Which is it?
Let's face it, if you could do a high intensity "burn" of calories you would be out their running and not reading this blog. But here you are thinking about riding a bike... I hate to break it to you but when you first start out all you can really do intensity wise is what you have been "training" for up to this point, which is probably just walking level of excretion, which would probably take over two hours to burn off 250 calories. But on the other extreme a fit cyclist could probably burn that off in 17 minutes (more on how I got that number in the Read More.) The problem of course how do you get form where you are to the other end?
This is where the power of the bicycle comes in
Distance: Do to the mechanical advantage of the bicycle you can go two to four times the distance with the same excretion as just using your legs alone. This makes for an opportunity to integrate bicycling into your daily routine by using it for transportation for trips 5 miles or less (for starters.) Doing shopping trips or biking to work are amazing ways to work in some exercise into a hectic schedule as just the time difference between biking and driving is the "negative" and the more you bike the smaller that difference gets. So basically for 15 minutes extra you can get in a good half hour of exercise. (Your experience may vary.)
Speed: Let's face it going fast is fun, going fast under your own power is even more fun. The people I have observed who successively used bicycling to control their weight have tapped into this aspect, whether consciously or not. I don't care who you are, when you are cycling and there is a head wind or a an uphill you are motivated to try a little bit harder to maintain speed. That push helps to get you a bit closer to burning 250 calories in 17 minutes. And just to keep things fun, for every uphill we have also installed a downhill and we even throw in a free tailwind every now and then to keep things fun.
Fun and adaptive for your (lack of) fitness level: This is the major thing I think most people miss out on, if it is fun you are more likely to do it more often and if your exercise of choice can "dial it down" a notch or two when you had a bit much is important, as time moving is the most important factor for health and the "intensity level" will get there when it gets there (and it will improve as long as you stick with it.) I will also note that I think having more then three gears is important to take advantage of what I am talking about as well as having the seat at the proper height (please see a bike shop to make sure, as most seats are too low which makes bicycling a lot harder then what it should be. And all you end up doing is hurting your knees rather then getting any sort of strength training.) When you are doing bicycling right you have the option of making it easier then walking. That is the power of the bicycle, as it can be easier then walking, harder then running and everything in between. You are in control of what you want to get out of it and the bicycle can grow with you as your fitness improves while never really losing the fun factor as the more you improve the more of the world you will want to see by bicycle.
Lose the ego
I have seen some people try cycling just to get thoroughly disgusted on how hard/slow it is to go up hill. Lose the ego, seriously. Any time cycling gets too rough down shift and go slower, no one is forcing you to speed up the hill. If you see a kid passing you on a tricycle just smile and say "Isn't that cute." and just do a pace that you can maintain. You need to trust that over time that will improve but only if you stick with it. If you make it harder then what it needs to be in the beginning you are not going to stick with it.
It helps to have this image
Your muscles are a lot like balloons, they need to be pre-stretched in order to blow them up easily. This pre-stretching happens automatically in the beginning (hills and wind, just to mention a couple of short random events that help this "stretching") but as you find yourself plateauing you'll need to add random pushes and challenges to make room for growth of muscles and to get a more calorie burn per minute.
3,300 cal Meal plans for the cyclocross season
You don't have to compete to enjoy the benefits cycling has to offer, you simply have to get out there and do it. Most people are amazed at the difference of what they can do now on a bicycle compared to what they were capable of a year ago.
So what I did was take the extra calorie intake in the above link over the standard recommended 2000 calorie diet divided by the amount of time exercising in that link.
1300 / 90 = 14.4 calories per minute
250 / 14.4 = 17 minutes
There you have it, a number far, far lower then what Johns Hopkins Bloomberg School of Public Health asserts is the "shortest" amount of time needed to burn 250 calories. (Granted this is not a perfect comparison as there is a large range in what is typical person but this is not too far off as a weight goal for many.)
So the choice is yours, diet alone, diet plus exercise or just exercise (and yes I know people who are keeping their weight in control just by exercising and eating in excess of 2000 calories a day. While I don't recommend just exercise as a starting point, you might find some comfort that at some point down the road "cheating" on your diet while exercising will not be cheating at all, you earned it.)
I hope you find my comments inspiring to get on a bike. Enjoy life! That is what it is there for.
And don't forget to check out your local bicycling club, as many have beginner rides where you can ride with people much like yourself.