Hoping you can tell me, is vegetarian diet an effective way to lose weight?

Not necessarily : What's effective for weight loss is the proportion of complex carbohydrates to protein to healthy fat. If someone is vegetarian but consumes a lot of processed starch and sugar they will have a hard time losing weight. As a vegetarian it's very important to take into correct amount of protein since a lot if protein is mixed with starch. I have many vegetarian patients are obese and go on a diet.