Although any of the below signs could mean you’re losing muscle, the only way to know for sure is to check your body composition (or your percent fat vs. muscle) once a month. The easiest and most trustworthy method is for your doctor or personal trainer to use a skin caliper. “You really need to go to someone who’s qualified. It needs to be done right or it won’t be consistent,” says Clayton. (Torch fat, get fit, and look and feel great with The 2 Week Diet NOW!)
The good news is, by being smart about losing weight you can maximize fat and minimize muscle loss. Keep an eye out for the following signs that can mean your body’s burning muscle.
Watching the pounds fall off is the worst…said no one, ever. That said, there is a limit to how much fat your body can shed. Dropping more than about two to two-and-a-half pounds a week usually means you’re tapping into your muscles as an energy source, says Albert Matheny, C.S.C.S, R.D., founder of Soho Strength Lab. Of course the number on the scale can be deceiving, and lots of other factors—like eating a super-salty meal the night before you weigh yourself—can affect it. But if the weight is falling off and you’re experiencing any of these other symptoms, there’s a good chance that some of the weight you’re losing is muscle.
Anyone who’s ever tried to hit the gym after a late night out knows you just can’t go as hard—and the same goes if you’re overdoing your diet and workouts. That effect compounds so that, over time, you’ll work your muscles less and they’ll be less able to repair themselves, resulting eventually in muscle loss. “It’s a downward slope,” says Matheny.
Since feeling sluggish can be a squishy metric, Clayton suggests quantifying your workouts with an activity tracker. If you can’t run more than 1,500 steps when you used to hit 2,000 on your morning jog or burn 500 instead of 700 calories in your HIIT class for a couple of weeks on end (and you’re getting your normal amount of sleep), there’s a good chance your body has started digging into the wrong reserves.
The point of hard workouts is to create tiny tears in your muscles that your body repairs between sweat sessions to make you stronger. But if you don’t give yourself enough fuel and time to recover, your muscles will waste away instead of rebuilding. In turn, you’ll notice you’ve plateaued and won’t be able to pick up the tempo or lift heavier weights. “A lot of factors affect performance, but not seeing progress in training is a good sign you’re not hitting your body’s needs,” says Matheny.
Thinking takes lots of energy: In fact, your brain alone uses about 20 percent of the calories your body needs for its most basic functions, according to Basic Neurochemistry: Molecular, Cellular and Medical Aspects. That means not eating enough definitely effects how well your brain works, resulting in brain fog and crankiness. And since your brain tells all of the muscles in your body what to do, when it’s running on energy reserves (i.e., muscle) you won’t be able to work out as efficiently either. “Our nervous system works hand-in-hand with our muscular system,” says Clayton. “Your brain has to be working well for rest of your body to be working well.”
For the same reason that you might feel sluggish or out of it, you might have a hard time keeping your balance: Your brain simply doesn’t have enough calories to communicate well with your muscles, and your performance suffers. “If you have low blood sugar or haven’t fully recovered, you’ll definitely not be as with it or focused, which could effect your balance. Your performance might not be as sharp,” says Matheny.