Anything you dedicate around a year on, you'll get good at.
- Calories, overall, are mostly the only thing that matters. Lose weight? Less calories than your maintenance calories. Gain? Eat more above maintenance.
- Lifting weights is the most efficient way of losing weight or building muscle because you have an equal amount of resistance every workout. If you run, you can run 10km one week, 15 the next, and so on and so on. With lifting, its (mostly) the same workout, but the weight increases, so the intensity is always the same.
- Lifting, sleeping correctly, and eating really well will create a beautiful trifecta in your life. You don't get irritated, you're crazy confident, you love yourself, it helps SO much with depression, you are more focus and aware. Life is just better, you genuinely love life.
Every day I wake up BURSTING out of my bed with energy. None of that grogginess.
I basically just did powerlifting, (3 days a week with deadlifts, bench, squat, and technical weightlifting for fun like powercleans, cleans, front squats, clean and jerks).
However, I can't run more than a kilometer.
One question though... Doesn't your theory of "Just add weight" apply to running too? Instead of weight, you add speed. So if 10km over three 25 minute workouts gets too easy, then run 11 in the same time. Then 12... Then 13... Keep the target intensity (heart rate) the same. Similar applies to biking, swimming, incline walking, or any other cardio activity.