Actually HIIT (High Intensity Interval Training) works wonders on loosing body fat.
Not for me. It only helped me to stay at roughly the weight I was when I started doing those for 9 months, a few years ago.
I have lost almost 43 kg (95 lbs) of weight in total during the past 5 years, and to me the best and fastest way to lose weight was a
combination of weightlifting/upper body workout and walking.
Here's how my usual week looked like (nowadays a lot more, but that's a different thing):
Monday - situps, biceps, back, pressups, chest
Tuesday - walk
Wednesday - situps, biceps, back, pressups, chest
Thursday - walk
Friday - situps, biceps, back, pressups, chest
Saturday - walk
Sunday - recovery and sauna
And the idea was volumetric training of sorts, ie. the amounts increase steadily. When I started, I did: 30 situps, 15 biceps, 30 backs, 10 pressups, 15 chests, and for walking: 4 km (2.5 miles). And then after every session, I would increase the workout amount by +2 or +1, and after every month, I would increase the walking distance by +1...2 km (0.6 - 1.2 miles) resulting in progress like this:
Monday - 30 situps, 15 biceps, 30 back, 10 pressups, 15 chest
Tuesday - 4 km walk (40 minutes)
Wednesday - 32 situps, 16 biceps, 32 back, 11 pressups, 16 chest
Thursday - 4 km walk
Friday - 34 situps, 17 biceps, 34 back, 12 pressups, 17 chest
Saturday - 4 km walk
Sunday - recovery and sauna
And the monthly progress for walking:
January - 4 km (40 min)
February - 5.5 km (50 min)
March - 6 km (60 min)
April - 8 km (70 min)
May - 10 km (75 min)
In the end, my upper body workout amounts were thus (halfway through the program, I changed my pressup technique to a more clean one, halving the reps)
Monday - 160 situps, 80 biceps, 160 back, 35 pressups, 80 chest
Tuesday - 4 km walk (40 minutes)
Wednesday - 162 situps, 81 biceps, 162 back, 36 pressups, 81 chest
Thursday - 4 km walk
Friday - 164 situps, 82 biceps, 164 back, 37 pressups, 82 chest
Saturday - 4 km walk
Sunday - recovery and sauna
Then during the summer, I got access to a gym at work, so I started doing a whole different kind of exercise routine.