Carbs can be a divisive topic—some people love them, some people hate them, and some people know that the answer’s not so black and white.
One thing we can count on right now is the popularity of “carb cycling.” A lot of people are into it. And though we can’t cover all of the different variables at play in a single article, there are a few strategies and findings from research that you should know about when deciding whether it’s right for you.
In this overview, I’ll break down what carb cycling is really all about, its potential benefits and drawbacks, and a few of the approaches you might take when trying it out.
What Is Carb Cycling All About?
Carbohydrates, which are stored as glycogen in both muscle and the liver, are the primary energy source we use during training. Intense endurance training relies on carbohydrates for fuel to a greater degree than resistance training, but lifting weights can definitely still cause a decent amount of glycogen depletion. Altering the glycogen content of our muscle before, during, or after training can lead to different training adaptations—and that’s where carb cycling comes in.
Carb cycling is simply a strategy for rotating between high-, low-, and moderate-carbohydrate days. (There are a few different ways to do this; we’ll get to that.) Carb cycling first became popular in endurance training because research suggested it might enhance adaptations to endurance exercise.
Because glycogen storage fuels training, promotes adaptation to training, and even influences muscle protein synthesis (the process through which we build muscle), researchers began to wonder if it was actually a key for endurance athletes. (The muscle-building piece also created some intrigue around carbs and resistance training.)
The Benefits of Carb Cycling
One of the major components of carb cycling is that you’ll perform some workouts in a glycogen-depleted state, meaning you exercise without solid carb stores to fuel you. While it might not sound fun, these workouts may promote the creation of mitochondria, which make muscles more efficient at producing energy (especially from fat) to improve endurance performance.
In fact, research has also shown that pairing carb cycling with specific training strategies can lead to greater fat loss than training without manipulating those carbs in as little as three weeks.
Wait, though. Haven’t we all been told that consuming carbs before workouts is necessary for optimal performance and gains? The theory behind the carb cycling stuff is that training in a low-carb state can actually increase the physiological stress of the workout. Typically, you’ll stick to lower volume or intensity workouts when in a low-carb state. The thing is, this theory suggests that you may induce greater stress and promote similar adaptations as you would during high-intensity, carb-fueled workouts when training sans carbs.
3 Ways To Carb Cycle
With this in mind, there are a few approaches to carb cycling you might want to consider—especially if your weekly exercise routine includes high-, moderate-, and low-volume workouts.
1. Train High, Sleep Low, Train Low, Repeat
This approach is a bit of a mouthful—and requires that you alternate between high-volume and low-volume workout days throughout the week. It’s also one of the most heavily researched in endurance sports because alternating high and low training volumes is extremely popular in endurance training.
The easiest way to visualize this is to imagine a typical training week.
On Monday, let’s say you crush a high-volume leg workout (because that’s the best way to start the week, right?). This is your “Train High” workout because it’s high-volume and longer in duration. You’ll eat carbs throughout the day before you train so your glycogen stores are fully ready to go when it’s time to hit the weights.
However, once your workout is over, you’re done eating carbs for the day. This is where “Sleep Low” comes in.
The next step is to perform your Tuesday workout in a low-carb state. Yep, this is your “Train Low” step. This should be a shorter workout with less volume and overall intensity. A steady-state cardio session or even an arms workout would be a good idea here. As soon as this session is over, you can start eating carbs again to restock muscle glycogen stores.
Finally, the last step is to “Repeat” the cycle. Your Wednesday workout puts you back at “Train High,” and can be another crusher in which you consume carbs beforehand. From there, you’ll continue to repeat the process, skipping carbs until after your lower-intensity Thursday workout.
One caveat here: Since resistance training recovery requires ample protein, you’ll want to increase your protein intake to account for the fewer carbs you consume after your heavy workouts. (Consuming protein without carbohydrates post-workout has been shown to lead to similar gains to consuming protein and carbs in the long-term.)
2. Fuel for the Work Required
This carb-cycling method is a little easier for most bodybuilders or powerlifters who aren’t always going to perfectly alternate high- and low-volume workout days. This method simply involves planning out your carb intake based on your training on a given day.
So, for high-volume leg days on which you train hard for at least an hour, you’ll want to have a high-carb day to support your training. Then, on upper-body days that aren’t quite as challenging, you could probably get away with a moderate carb intake. And, finally, on rest days or cardio days, you can go low-carb since you don’t have any intense training to fuel.
This is, by far, the most flexible method and thus probably the most popular method of carb cycling amongst strength athletes. It creates a scenario in which you’re always fueling appropriately for your training on a given day, helping you avoid both going overboard on carbs and falling short on them.
Many people add a “Sleep Low” element to this method, meaning that you would sleep on low-carb stores. However, this should really depend on what time of day you train; it’s easier to avoid carbs after an evening workout than a morning one. If it works for you, this “Sleep Low” element can extend the amount of time your muscles spend in a glycogen-depleted state which can boost mitochondrial density and fat-burning in the long term.
This last method can be super-beneficial to bodybuilders who want to cut body fat. Many bodybuilders undergoing a cut start their day off with a fasted cardio session then do their lifting workout later in the day—but what if we reversed that?
Studies have shown that performing a heavier and/or higher-volume, carb-fueled session in the morning, avoiding carbs all day after, and then doing a lighter session in the evening while carb-depleted can increase whole-body fat burning.
For starters, this is partly due to the fact that the first workout is performed in a “fed” state, in which muscle glycogen content is at least moderate. Combining this with a carb-depleted workout at night can be a great method to maximize fat burning.
The best part: You can still eat carbs after your evening session, so you don’t necessarily have to “Sleep Low” with this approach. Since your heavy workout is in the morning, eating some carbs before bed can help increase muscle glycogen content for it.
Are There Downsides to Carb Cycling For Lifters?
One thing to note for resistance trainers: If being carb-depleted impacts your ability to train to your needed volume and intensity, your low energy levels can ultimately impact your gains. For this reason, I recommend thinking of carb cycling as a tool, not a law. If you’re in an intense gaining phase, for example, you might want to limit your lower-carb days to rest days. Since just about every workout in a phase like this is longer and higher-volume, you want to make sure you have appropriate carb levels to fuel that intensity.
Also important to keep in mind? Doing intense training in a glycogen-restricted state can increase your susceptibility to illness, so planning your low-carb days appropriately is a must if you want to stave off illness and train hard. Always plan your low-carb days to fall on your easier workout days.
Limitations In The Research
One major issue that we see with carb cycling studies is that many of them simply don’t last long enough to determine long-term benefits. Most of the studies last for three weeks or less—and some look at specific changes (like gene expression) after just one or a few training sessions. And while changes in gene expression would obviously influence long-term adaptation, we still don’t have many longitudinal studies to truly map that out.
Another shortcoming with the research on carb cycling is that it focuses so heavily on endurance training, so the topics it emphasizes and results it finds may not be as relevant for strength athletes.
Plus, though the latest research is concerned with discovering the “sweet spot” for muscle glycogen levels and exercise adaptations, we don’t have all of the answers on the “best” carb cycling plan quite yet.
The Bottom Line on Carb Cycling For Weightlifters
The research into carb cycling is still emerging—and not all of it applies specifically to strength athletes. More research on carb cycling in this group will help us better understand the potential benefits.
In the meantime, it’s important to allocate your carbs according to your training intensity. Since taking this tailored approach to your nutrition and training can be tricky over time, I think the easiest way to plan your carb intake is to fuel your training and promote recovery while being mindful of the days that you don’t need many carbs. As long as your carb intake supports your goal for a given day, you’ll be fine.
With that in mind, carb cycling can be a great way to modulate weight loss or weight gain. Based on the research, using carb cycling as a strategy to minimize fat gain during a bulk or maximize fat loss during a cut is a smart idea.
Of course, many factors influence how an individual person will react to a specific diet. As with training, some people will be high responders to certain programs while others won’t respond at all. No training plan—or diet approach—is one-size-fits-all, so try out the different methods here and be honest about whether or not they work for you.
Known as ‘The Muscle Ph.D.,’ Dr. Jacob Wilson has a knack for transforming challenging, complex concepts into understandable lessons that can support your body composition and health goals. A skeletal muscle physiologist and sports nutrition expert, Wilson is a leader in muscle sports nutrition. As the CEO of The Applied Science & Performance Institute and researches supplementation, nutrition, and their impact on muscle size, strength, and power.