When someone wants to lose a substantial amount of weight, there are two places that they might turn, and this the local gym, and also the internet. While both these things can be of assistance, there's someone else who you should turn to. When the amount of weight you're looking to shed is significant (as opposed to merely dropping a kilo or two), then you should have a talk with your GP.

Your Body Mass Index

Your GP can help you to determine your goal weight, since you need to have a target, instead of active weight loss becoming a lifelong strategy. This is often a matter of calculating your body mass index (BMI), which dictates your healthiest weight based upon your height. BMI is generally calculated by taking your existing weight (body mass) and dividing it by the square of your height. Your doctor will also be able to help you formulate a healthy schedule for your weight loss, so that progress can be broken down into manageable units of time.  

Your Medical History

Your doctor will know your medical history and how any prescribed medications (such as antidepressants) might be causing you to gain and/or retain weight. Your doctor will also know how your weight loss goals can affect the type of medication you require. Losing weight can also change your medication requirements for certain conditions, such as type 2 diabetes, and hypertension. In some cases, your doctor might even prescribe medication to aid with your weight loss, and it's always preferable to receive this assistance from a medical professional, instead of taking over-the-counter weight loss drugs. 

Weight Loss Surgery

Your doctor can also make the call when your weight loss efforts might not be sufficient, as in they can tell you if you're a candidate for bariatric surgery. Gastric bypass surgery is perhaps the best-known form of bariatric surgery, which involves the surgical sectioning of your stomach so that you ultimately will consume far less food. This is typically only performed on patients with morbid obesity, with a subsequently excessive BMI. This is why the assistance of your doctor to pinpoint the difference between your BMI and goal weight can be helpful in determining your suitability for surgical assistance. If you are a candidate, you should also discuss the possibility of body contouring surgery, which can be necessary to remove excess skin after your weight loss.

It's not as though your doctor can magically fix your weight issues, but their assistance can be invaluable when there's a considerable amount of weight that needs to be lost.