Yes, people report that after Tabata they are physically exhausted. While I feel I do get some benefit from Tabata on my bike, I dont feel as stuffed as I think I should. I think it is due to not having nough resistance on my magnetic trainer.
Front squats tabata sounds great, but I think OP has purchased a bike for pleasure and fitness, and is wondering how to get best results for fat loss using his new bike.
Riding for 3-4 times a week for an hour will definately show results, but like you mentioned its all about diet. I agree on lifting some weights.