If you are looking to build anything (house, high rise, furniture, cake) the most important aspect is having a solid foundation. With out the building blocks at the bottom you will never be able to support anything significant at the top.
Your fitness is no different, people are always looking for the easy way out. The 4 minute this, the 30 second that, the perfect program to get you ripped or the strap in and shake the fat away belt!
The truth is that yes, these methods will probably work initially, but so will just about anything in the beginning. Your body is an amazing creation and will adapt itself to cope with any new stimulus. But to truely get the benefits of high intensity, short work outs you need to earn the right to do them by building a strong foundation first.
Following these short term fixes for extended periods when you are not ready for it, in the long run is a path to nowhere. It's like trying to build a pyramid with the point at the bottom. Sure you can build a few layers on top, but eventually it will come tumbling down, you will get injured and you will have to build back up from the beginning.
While it isn't as glamorous and probably not as fun. The best method to begin training with is a solid foundation, of lower intensity cardio efforts or lighter controlled resistance training work with a focus on perfect technique.
Building this solid and stable base means you will always have a solid foundation that you can fall back on.
Beginning you're training this way is not a quick fix, it will take time but it will also lead to better results and less injury in the long term.
Your fitness is like everything else in life. If it sounds too good to be true. It probably is. So put in the work build your foundation and keep it for life.