Empty Stomach versus Full Stomach
There have been researching studies that show both the pros and cons of exercising on an empty stomach and if it really matters. In my opinion, doing cardio on an empty stomach versus eating a light snack about an hour before is controversial.
The theory is, if you work out on an empty stomach, you will burn more fat calories because you will not have any food in your system to burn through, therefore achieving lower body fat.
If your goal is to only worry about tapping into your fat stores then this may be an option for you. My argument is, if you are exercising on an empty stomach, are you going to have enough energy to have an intense workout, which in my opinion is more important for long term fat/weight loss.
If you are going for endurance, you most definitely do not want to do cardio on an empty stomach as it will reduce your aerobic capacity.
A clear cut answer from me would be to eat a light snack an hour before, so you can have more energy during your cardio workout but not have too much food to burn to get to your fat stores.
Cardio in the Morning Versus Late at Night
Many fitness professionals recommend that cardio be done early in the morning because of the fasting that has been done after eight hours of sleep.
Once again I think this is questionable, and it is all about personal preference. Doing cardio in the morning for some people allows them to have more energy throughout the day and facilitates a clearer mind.
Doing cardio in the evening can, for some people like myself, actually have more benefits. The nutrients that you have eaten and the water you have drunk throughout the day is in your system to be used. I personally have more energy in the evening and find that I push myself harder at night.
I am a believer that everyone has a different peak workout time and that one should figure out that time and use it to their advantage.
In my opinion, it does not matter when you do cardio in the day as long as you get it done effectively.
The Speed of Your Workouts and Weight Loss
It has been taught for years that the slower your cardio exercise the better it is because it burns more calories from fat.
You must define what your goal is and what you want for the long term first before you come to any conclusions on your training style. I think that you can lose weight doing either slow, less intense exercise or fast, high-intensity workouts.
One thing that I would encourage you to look at is how you want your body to look. Compare the look of athletes from different sports such as marathon running and track sprinters. You will notice the difference in how their bodies are shaped.
There is no one superior way to the other and so it is just about what your goals are and what you want to look like.
If you are going for a long lean and not as much muscle on your body look, then do long-duration workouts like cardio. If you are looking for a more muscular and defined frame, then do the higher intensity and faster workouts.
My Advice for You
Try the methods that I presented to you above, test them on yourself, and see how you feel, how your body changes and reacts, and the overall results that you get.
If you are getting closer to the results that you are looking for, then stick with that program and train using those techniques.
I am not a believer in there being only one way to train. I just believe there is a systematic approach you can take to fitness and then it is up to you to test those approaches to see what works best for you.
We all have different bodies so we need to find out the best ways to train ourselves.