Overweight pregnant lab

Question
What is a safe way to help my pregnant lab lose weight without harming the puppies?  She is 30 days pregnant right now and weighs 95 lbs..  We have started to exercise her several times a day and are currently feeding her the recommended amount of dog chow for her weight class.  I haven't cut her food intake for fear of taking away nutrition the pups may need and haven't changed her to a food better suited for a pregnant lab for fear of the added fat content.  Thank you so much for your help.

Answer
you cant diet a dog wehn shes pregnant! she should have been slimmed down before getting pregnant over exercising or underfeeding her at this stage will cause her to loss the puppies, Get her back to her playing weight after the puppies are weaned and not a moment later!