It really depends on how you do it. Lifting is anaerobic, so you do best, if you want to lose weight, mixing it with aerobics -- running, time on the walker or the treadmill. However, aerobics bores me to death. If you do a lot of supersets and circuits with the weights, not resting much between sets so you keep your heart rate high, work to muscle failure, till you are soaked and dripping and you are breathing really hard, you will lose weight or keep it off, assuming you eat right and drink a lot of water.
I know I should do more aerobics, and I'm trying to mix them back in, but after several years with very little aerobics and lots of serious high-intensity lifting, my weight has plateaued at about where it was when I more or less cut out the aerobics, and I have a lot more muscle and the same body fat ratio.
My trainer says I could lower the body fat ratio if I did more aerobics and more high impact work, but that's not really a goal of mine. My body seems to like this set set point, and I don't see the point of getting a whole lot more cut that I already am.
This regime, roughly 4-5 days on with serious lifting, initially with 15-25 min of aerobics a day, lowered then to 12-15, now (last three or so years) to 15 min maybe twice a week every other week, takes me may 40 min start to shower; minimum junk food, lotsa veg and lots of water, and I'm in better shape than I was at 25. Less flexible, of course, that's advancing age.
This routine isn't for everyone; you have to be a fairly serious ironhead, but I like it, actually I feel bad if I have to miss a day or a week. The research supports this effect. The aerobics are good for your heart, lungs, and endurance, so I should mix those back in more.
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