OK what is the best way exercise routine to lose the gut for a 35 yr old male?

sorry, but doing sit ups isn't going to cut it. you have to add cardio to your exercise regime to slim down all over. that way you can tone up your body. I'd say hit the gym, sweat it out at least 4 -5 days a week. don't forget to add resistance training to burn more fat as well. best of luck.