Is it not ultimately true that energy taken in minutes energy burned = gain in mass?
For a human body, it's complicated as we burn calories at different rates, process our food differently and have the weight of water to think about. But ultimately, it seems to me that calories are the important factor in weight loss/gain.
What your body's made of (muscle/fat) is another matter but I'm not sure that studies showing tiny differences in weight loss efficiency on specific diets are all that useful.
Anyway, we'll get one data point from how it goes with me in the coming months. I've been around 200lb for a few years and am now properly trying to cut. This is mostly a) to get faster at running and b) to be a good example for my kids.
I have generally been highly active with a very high calorie diet. Too much junk and too big portions. That's changed now - simply tracking my intake and being calorie-aware has improved things.
I'm also being more active, and may be able to make some strength gains while cutting fat. I'm on 3 runs a week (approx. 18km total) and have begun kettlebell work. 16kg bell, simply doing swings at the moment. I'm working towards 500 swings per workout, broken up into clusters of 100, considering of 10/15/25/50 reps.
3 workouts in and I'm up to 350 reps. I could probably have done 400 this morning but had to get to work. Grip strength is the big limiting factor at the moment though - and not helped by getting the bell wet from dew.
I'm not expecting anyone to read this rubbish, this is more to mark a point - and hopefully I'll be able to look back in a few months and see some major improvement. All a bit dependent on how things go with baby no. 2, due soon.