It depends.

Running is arguably one of the most efficient ways to burn calories but if you are not a runner yet and haven’t been active for a while there are some considerations you have to make.

Before you adopt running as a method of weight loss, you need to think about what actually happens to your body when you run.

During each foot strike the body is exposed to repeated impact which forces are estimated to be 2 to 3 times the body weight of the runner. Applying this fact to the average runner 68Kg(150-pound), who has an average of 400 foot-strikes per foot per mile, during a one-mile run each foot would endure between 60 and 90 tons of force. 

Typical runners who train from 40 to 80 miles (av. 60km) per week could expect to expose their bodies to approximately 16,000 to 32,000 impacts per leg per week, equivalent to about 2400 to 7200 tons of force. 

This is an astounding amount of stress to the lower extremities that increases the likelihood of injury. 

Before you go all in on the road, strengthen the muscles of your legs with low impact training (resistance training). 

Resistance training will reinforce good mechanical awareness and ensure good structural balance around joints. 

Example

Free body exercises or weight training exercises like squats, lunges, deadlifts, leg extensions and hip bridges can prepare you for high impact activities while still burning calories.

Combine these with swimming, brisk walks or cycling to start with and make sure you stretch calves, hamstrings, quads and gluteus to release the strain on your legs.

Find the safest way for you to increase your energy expenditure (calories out) and keep progressing as your body gets fitter.

If someone tells you to run in order to lose weight without taking your current fitness level into account, I would question their methodology.