After weight training your body depleted its glycogen stores. So the interval training will put you in your fat burning state quicker. the key is working harder for a shorter amount of time for cardio. I only do it for 10-15 min after i weight train and boy am i huffing and puffing. Also alot of guys out thier load up on way to much protein. Protein in excess is just extra calories and it will prevent you from being LEAN. Thats why thiers alot of fat muscular guys in the gym

Also a caloric deficit does not mean a protein deficit. I went from (5’10) 200 pounds to 185 at 9 percent body fat. And yes I built muscle while LOOSING fat it was a EYE OPENER. I was stuck on a bulking phase gaining all this fat then i had to cut it all away it was SO frustrating. If you wanna get friggen lean after your weight training do some interval running. walk for one minute on the treadmill then run hard for a minute. Repeat this lets say 10 times and you will burn fat calories.

Its VERY possible to gain muscle and loose fat at the same time. But you need a small caloric deficit of maybe 300-500 calories maximum. This way your body does not go into starvation mode and burn muscle. Your body will take the extra calories it needs from your FAT stores. Its only hard when a individual has maximized muscularity and minimized fat aka bodybuilders going to a competition that its hard to do both. But if you have some body fat on you your able to build muscle AND loose fat.