Fats are not made equal. Some fats are vital for the health of our body, and some may cause ill health if consumed in excess amounts over a period of time. By including healthier types/sources of fat in appropriate amounts in our diet plan, it can help to promote our wellbeing and prevent certain diseases.
Studies show that basic cardio performed routinely actually ends up not giving you the fat loss potential as when you first started. Excessive cardio, like running on a treadmill 5 days a week for hours, has shown to decrease natural hormone production like testosterone, and could even weaken the immune system.
There are many different reasons why the 5x5 program ends in failure, but those who succeed have truly increased their size and strength.