I read an article by a woman triathlete who was trying to lose that type of weight. She was calorie conscious and regularly training but couldn't get rid of it. The article referenced a study that used 2 groups of women. One group did 45 minutes of high resistance training and the other did 20 minutes of interval training. The study measured HGH levels and found them elevated in the interval group.
The interval training group lost more weight overall. I will say that it supposedly had to do with fast twitch muscle as opposed to slow twitch muscle. I will say supposedly because that is a source of controversy.
I will try to find that article as I found it quite interesting.
ETA a couple of interesting links. Lots out there. Although I believe that a strong base is desired which comes by time in the saddle, intervals and hill repeats have a great benefit.
4 weeks of high-intensity interval training does not alter the exercise-induced growth hormone response in sedentary men
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363223/
11 Research-Backed Reasons You Should Be Doing HIIT Instead of Traditional Cardio
https://www.trainforeverstrong.com/1...tional-cardio/