Shedding weight is all about burning through your daily calories and tapping into fat for energy. But run on an empty tank all of the time and you’ll work against your best efforts. “People who are trying to lose weight sometimes think they have to go on a crazy diet and work out five times a day, but they’re stressing their system too much,” says Nick Clayton, C.S.C.S., the personal training program manager for the National Strength and Conditioning Association. When your body gets too stressed, it thinks you’re starving and goes into survival mode—and its only motivation at that point is to ensure you have the energy for essential functions like breathing. Without enough energy (i.e., calories) to keep those going, your body will tap into its own sources—which include both stored fat and muscle. Lose muscle, in turn, and your metabolism slows down. Since muscle burns more calories than fat, that’s totally counter-productive to your goals.
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 Women's Health's All in 18 DVD!)
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.
Looking for a healthy snack? Try this protein-packed vanilla almond yogurt dip:
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.
Related: The Exact Abs Workout That Helped Mama June Go From 460 Pounds To A Size 4
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.
Related: 'The One Change I Made To Bust Through My Plateau And Lose 94 Pounds'
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.”
Related: 'I Tried The Tone It Up Plan To Lose Weight—Here's What Happened'
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.
Colleen de Bellefonds is an American freelance journalist living in Paris, France, with her husband and dog, Mochi. She loves running, yoga, and wine, and is very particular about her baguettes.
