Best interval training for fat loss

Best interval training for fat loss?

I do interval training 4x a wk for 45min+

When using a treadmill, would it be more beneficial for me to do:

2min rest period (uphill walk) followed by 1min sprint (13.0km/h)
1min rest period followed by 1 min sprint
2 min rest period followed by 3/4 min run (12, 13, 14, 15km/h)

My aim is to shed fat while mainting muscle!