This
Weight-Loss and Weight Lifting - New York Times article may not be accessible unless you register, so I'll paraphrase as much as possible. It's a little disheartening, but not as much as I originally thought.
The article says that almost every weight loss book available says something about lifting weights/strength training as a way to lose weight easier and faster because lifting weights build muscle, and muscle burns more calories than fat. Ok, yes, we have all heard that one.
The article then goes on to say that this actually doesn't work for most women for two big reasons:
1. Because women who lift weights for weght loss also cut calories, and it's very hard to increase muscle while dieting.
2. Women who lift weights fail to use heavy enough weights or progress to heavier weights. This makes perfect sense. If you aren't lifting a heavy enough weight to challenge your muscle, all you are really doing is really, really light cardio. About the only advantage of ultra-light cardio is that you aren't on the couch with a bag of potato chips!! The article actually shows a picture of a woman's had with a weight in it that an infant could lift - yeah, no wonder that's not doing her any good.
Ok, these make perfect sense, so if we are progressively lifting heavier weights and lifting enough to make us sweat and breathe hard is that going to help? Well, here's the disheartening part.
The article says that "studies show that even women who do what it takes to get stronger develop only two to four pounds of muscle after six months of progressive lifting. Given that one pound of muscle burns between 7 to 13 calories a day .. snip explanation .. that means the average boost in metabolism is only 14 to 52 calories a day."
Well, that sucks. And it gets worse ... they also did a study of 59 women with all woman walking 5 days a week and only eating 1200 to 1500 calories a day (egad, can you really live on that?!?) and some also did strength training and some also did yoga. The ones who did the strengh training and the yoga lost no more than the other ones.
Well, I say that how do we know these women were really working the weights? How do we know they weren't doing the 1/2 pound dumbells only? Plus, how do we know they weren't slimmer, even if they didn't lose the weight?