The bicycle is one of the best tools to use to burn calories and lose weight. A 145lb woman riding 1 hour at about 12 MPH will burn about 500 Calories, up the speed to 16 MPH and the calorie burn increases to about 835 Calories per hour.
You can increase calorie burn by doing sprints now and then during the ride.
Since it takes 3500 Calories to burn a pound of fat, then about 4 hours of cycling at 16 MPH will burn roughly enough calories to burn 1 pound of fat.
Cycling is very low impact, so it does not take the toll on the joints like running does.
Cycling can be done indoors on a stationery bike when the weather is bad, with little or no change in your calorie burn.
Personally I find indoor cycling on a stationery bike boring, but some find it quite fulfilling and there are now simulation machines that make it seem as if you are going on a course rather than just riding the bike. Some of these work with a trainer and increase resistance when going up hills and offer a variety of course to keep the boredom down.
You can use the bicycle to do some errands and at the same time burn some calories that you would never have had the chance to do otherwise. The use of a small bicycle trailer increases the number of calories burned as well as offer more opportunities for errands since you can carry much more and that allows you to expand the errand you can do.
What I mean by that is that with my trailer I can carry up to 100 lbs. of groceries or tools or whatever. I have carried week's groceries back from the supermarket. Pulling a 100lb load up even a small hill will put a lot of extra resistance on the pedals and improve your leg strength.
Most people think of the bicycle as a totally cardio workout, but that is not always true. Taking you bike up hills, especially with the extra load of a trailer will definitely increase leg strength and it will also be a great way to strengthen your core.
If you ride BMX or Mountain Bike then you will also build some upper body strength and your will burn a lot more calories than if you just ride casually.
Depending on the type of cycling you plan to do there may be some preparation needed and will depend on what type of bike you want to buy.
You should check with the local shop, they are usually very helpful. Yes they want to sell you a bike, but most shops realize that they want to make you happy even more and if they sell you something that does not fit, you will not come back. Since they need your repeat business in order to stay in business they will almost always do their best to make the bike you buy be the bike you will ride.
Here are some general rules, but not always a perfect fit since every individual is different.
Buy a road bike if you are wanting to lose weight, get fit, would like to ride with groups and enjoy the speed and agility of road biking in general. If you do that also check with the shop about how to get into the local bike club or group and have fun getting fir. I am a member of the Pecan City Pedalers in Albany Georgia and also have contacts in clubs all over the US. I very much enjoy road biking.
Buy a comfort bike or hybrid if you are just interested in fitness and do not mind riding alone, do not really care about speed but just want to burn calories and get fir. These will usually have narrower tires so they will go a little faster. They are a sort of cross between a Mountain Bike and a Road Bike.
Buy a Mountain Bike if you live in an area where there are a lot of back roads that are not paved, road bikes and hybrids do not do the loose gravel and grass thing as well as mountain bikes do.
Cruisers are OK, though not my own choice. That was the main type of bike that existed when I was a kid. These are sort of single speed bikes like we had back in the 50's and 60's Would be OK for tooling around town, but they can be really rough on hills.
BMX Cruisers or 20 "for racing. Racing BMX can be done at any age and after the first few times around the track you will either love it or hate it. Most children love it, adults not so much. Personally I enjoy it and love riding and even racing with my grandchildren. It gives a great workout and after 3 Motos (1 race) I feel like I have gotten a good workout.
If you try BMX, rent a bike or borrow one, most tracks have them at the track and will rent or loan one for a practice race. Once you have tried it you will have to decide for yourself if it is for you. BMX Racing is not for everyone, but everyone is welcome to try it. I think it is a lot of fun, but maybe when I get old (I am only 57) I will think differently.