I believe you can do it on your own. I know how hard it can be, I was a heart attack waiting to happen. Then the best thing happened to me, I was diagnosed with Type 2 Diabetes. Now I know this should be the worst, but it was the catalyst for me to put into action a change in diet and exercise.
The hardest thing is starting, I don't care what anybody says, with no results you will lose faith that you can do it.
Remember no matter what anybody says the formula for weight loss is really simple. Calories in must be less than Calories out. If this is the case you will slowly lose weight and this is the best method.
If you would like any tips I have created a Weight Loss website that will hopefully help you.