^^For losing weight it's calories in versus calories out. 3 pounds per week is a bit on the high side of being able to lose fat without dropping some muscle mass and strength.

You weight loss has probably stopped because:
A. Your interval workouts are shorter and don't burn as many calories as the longer rides did
B. Your weight has dropped, your body now needs less calories to maintain it's current weight, but you haven't made the adjustments.

You can get absolutely shredded while doing high intensity workouts, you just need to eat properly.

I do agree that different things work for better for different people. If I go gluten free, low carb, or paleo my performance suffers. Other people may feel amazing while doing those things.