While the low-carb diet can help you get ripped by cutting your bodyfat levels, it also can cost you valuable muscle size. That’s because stores of glycogen (stored glucose from carbohydrates) inside your muscle tissue and liver are compromised when your carb intake is too low. And with low stores of glycogen, it’s difficult for your muscles to exert the sustained, high-intensity effort required to lift weights.
Essentially, you suffer a decrease in strength, your training poundages drop and your muscles get less stimulation, which leads to muscle loss.
In addition, when you diet (whether a low-carb diet or otherwise), you’re almost always in a hypocaloric state (you take in fewer food calories than you burn). In this environment, your body looks for the “missing energy” it needs to function, usually breaking protein structures into amino acids, which can then be used for energy. Because of those factors, you need to structure your resistance training so that it’s brief, heavy and intense.
Brief workouts consume fewer calories than longer workouts. For those of you who don’t feel like you’ve had a good workout until you’ve spent the entire afternoon in the gym, remember this: There’s an inverse relationship between training volume and training intensity.
You can train hard for a short period or not-so-hard for a longer period, but you can’t train hard for a long period! In fact, if you truly give it your all on every set of every exercise, you won’t last longer than 20-30 minutes per bodypart.
You want to also go as heavy as possible as quickly into the workout as possible after a warm-up. This is important, because when a muscle is fresh, ATP (the chemical responsible for energy and contraction) and stored glycogen in the muscle are at their highest. That’s when you can generate really big power output.
Think of training your bodyparts this way: You should be exerting as much force as you can in as short a time as you can. Make maximizing the stress during your workout your first goal.