I've been having good success with switching to a ketogenic diet. I've only been on it for 2 months, but have lost close to 10 kg while maintaining my same workout routine doing swimming and body weight exercises. My friends have even asked me if I'm doing something because the weight loss is so obvious!

well be careful of diabetes in the long run. the human body was not meant to make use of ketones as a long term source of fuel for a reason.

I guess i need a nutricionist…

1. Cardio is great for the heart and circulation (whence the name), but this is independent of energy consumption.  Running 1 km, jogging 1 km, and walking 1 km all burn essentially the same amount of kcal above your baseline metabolism.  So, if you do similar exercises but at lower intensity, and you can do them much longer, then you will burn more energy.  Obviously, this choice also depends on the amount of time you want to spend and your overall fitness goals.

2. Increasing your muscle mass will also increase your baseline metabolism (which otherwise decreases as you lose fat), so muscle-building exercises can help, as well.  Again, this depends on your overall fitness goals.

3. All the fat-burning exercises in the world won't help if you get hungry and regain that energy in additional food.  Watching your diet is key.  If you have trouble keeping your caloric intake down, try eating more leafy green vegetables (like salad) and other vegetables.  Just avoid too many high-starch roots or too much added fat.  A little low-fat protein can help reduce hunger, as well.  Just don't go overboard.

1)  You may be retaining water, give it time.
2)  Calories in, calories out.  90% of losing fat is diet.  Cardio is great but you need to focus on diet to lose fat.

;D