There is no such thing as a one size fits all diet and exercise plan. If there was it'd make life so much easier. Different things work for different people.
I follow a low carb diet and that stops me from putting weight on. If I want to lose weight, however, I stick to low carb but reduce the calories.
Exercise wise - I go to the gym/out on my bike/for a run five or six days a week. Again, this keeps my weight stable. If I want to lose the pounds I up the I intensity.
Em