So, if you've got a significant amount of weight to lose, and you're lifting hard, the odds you will decrease your muscle mass from decreased carbohydrate intake is low. (anymanfitness.com)
Regular alcohol use lowers testosterone levels, which in turn means decreased muscle mass. (personaltraining4u.net)
Not only that, they also discovered that people who slept less had shown decreased muscle mass. (fitbodyhq.com)