I started exercising 6 months before going on a diet. I did Medifast and continued to work out. I do Jillian Michaels. On Medifast I kept my calories around 1100-1200 to be on the safe side. I switched to IP and did the same, but IP was too low in carb for me, so I had to give it up. I think it is best not to do intense cardio in combination with any low carb diet. Strength is fine, though you may not build muscles, just maintain what you have. I did build some on Medifast, but I started from zero.