If you want to lose weight but can鈥檛 stand running, lift weights instead. New research in mice shows that strength training is just as good as endurance training at burning off fat.
Running and other endurance activities build up what鈥檚 known as 鈥渟low鈥� or type I muscle. It is rich in mitochondria, the energy powerhouses of cells, and research has shown that this type of muscle combats weight gain and reduces the incidence of metabolic problems. 鈥淔ast鈥� or type II muscle 鈥� the kind you build when pumping iron 鈥� is mitochondria-poor and was thought to be less effective in reversing weight gain.
Kenneth Walsh at Boston University School of Medicine and his colleagues were curious to know how weight training affects metabolism. So they designed a mouse in which Akt1, a gene involved in building type II muscle, could be switched on and off by giving the mice a drug.
Advertisement
The mice ate a high-fat, high-sugar diet and got fat. But when the gene was activated, not only did the rodents鈥� muscles bulk up, they also lost body fat. This was despite them not exercising and continuing to overindulge (Cell Metabolism, ).
There were other metabolic improvements too, such as a decrease in fat around the liver. 鈥淚t was stunning,鈥� says Walsh. 鈥淭ype II muscle has been under-appreciated.鈥�
