Most of my workouts were 30 minutes long, and most weeks I did 5 workouts. The other part of the time was spent on commuting to the gym (10 minutes) or getting ready, etc. This is an important point, as most of my weight loss did not come from the exercise: I burnt about 400 calories at a time and immediately replenished them after. The weight loss came from the calorie restricted diet (not overly so, I did create a deficit), which included lots of vegetables and fruit.

I have tried doing dieting alone but it never worked: I could lose weight, but then would gain it back within a year. Combining diet and exercise completed the feedback loop. Eating like crap meant feeling like I was going to die when working out. Conversely, eating well meant performing well. This clicked for me.