The motivation has come with a solid backing of willpower—it’s time to get ripped. Knowing that every fitness routine is 70% diet and 30% working out, you’ve chosen the ketogenic diet to bring you closer to your fitness goals.
But if you’ve got the diet down pat, why not strike while the iron is hot, right? Compounding a good diet with a rigorous workout plan definitely sounds like the right thing to do when aiming high.
And while that is solid advice most of the time, the keto diet stands out in its uniqueness—at least when it comes to the workouts that should be matched with it.
As we’ll see down below, the keto diet’s strength is also a limiting feature when it comes to high-intensity exercises, such as weightlifting or high-intensity interval training. There are, as always, ways to get around this—so don’t be scrapping your diet just yet.
The ketogenic diet relies on putting your body in a state of ketosis—where the primary fuel being burned switches over from using carbohydrates to using fat stores.
This has the obvious benefit of burning fat, but its touted health benefits also include a boost in energy levels and less blood sugar swings.
A low-carb diet like keto relies on taking in around 70% of your daily macronutrients from fats, about 20% from proteins, and 10% from carbs. The ketogenic state from a high-fat diet (where your body begins using fat as its primary fuel source) usually takes anywhere from a few days to a couple of weeks to kick in. Before this happens, however, some people experience flu-like symptoms.
The name for this “sickness” is the keto flu, and it’s best to not dive into a rigorous resistance training program when your body is just getting used to the new diet.
It’s generally a good idea overall to only introduce new things into your routine one by one. That way you’ll know what works and what doesn’t—allowing you to make better decisions for your own individual case.
But to understand more about what makes working out on the ketogenic diet special, let’s take a closer look at how our bodies use energy to power through our workouts.
There are three different systems that our body utilizes to provide energy.
The first is the phosphagen system. Also called the ATP system, it uses creatine phosphate to give us very high-intensity bursts of energy for very short periods of time (in the seconds).
This system comes in use during activities such as sprinting and strength training.
However, the source of energy from this system runs out relatively fast, which is when the body turns to other systems to power it.
Glycolysis is the process that uses glucose for energy—what we make use of in our daily lives if we’re not doing keto. This energy system relies on the glycogen stored in our muscles and liver in order to keep us going.
This system is what powers our moderate-to-high intensity exercises, such as HIIT or weightlifting. However, our bodies don’t have enough of it to keep us going for longer periods of time, which is when they switch over to the aerobic metabolic pathway.
The aerobic system is what utilizes broken down fats (which are called ketones) in order to power the body. While this energy system has the ability to tap into a massive amount of energy on a person (all of the fat), it doesn’t have the ability to do so in high-intensity bursts.
This last aspect is what differentiates working out while doing keto.
We already mentioned that it’s probably not a good idea to begin a rigorous training program soon after beginning ketosis due to the keto flu and the general low energy feeling people get after severely limiting their carb intake.
However, as we saw with the energy systems, ketosis isn’t very well equipped to deal with high-intensity activities that require bursts of energy. Steady-state workouts that are low-intensity to moderate intensity (such as cardio workouts, cycling, or swimming) are best suited for a body being powered by ketosis since they allow you to draw from your fat reserves on a slower, consistent basis.
In fact, a recent study has shown that keto dropped endurance capacity and peak power output over a 6-week period in 42 research subjects. While the results weren’t detrimental enough to dissuade people off of keto, it’s an important factor to note if you’re looking to perform at high levels in sports or other activities.
However, these negative effects of keto can be mitigated with the proper diet. Let’s first take a look at what a conventional keto diet looks like.
We all know that keto relies on limiting carb intake, but what does that actually look like—especially when throwing a workout plan into the mix.
Protein is obviously king when we’re talking about getting shredded and jacked. Protein gives us the muscle mass and strength to make working out worth it. And while the dirty bulk is always a tempting aspect during winter, it’s not something that will meld well with a diet like keto.
Luckily, protein isn’t something that necessarily has a hard cap on it. The prevailing advice is to get between 0.6 grams to 0.9 grams of protein per pound of one’s bodyweight. And if you’re having trouble with that, there’s always high-quality protein powder to get you through.
Where exactly you place your macros in that range, however, is up to you and your workout routine. If you’re still looking for gains (or at least preventing gain loss), then it’s best to stick to the higher portion of that range. But while it might seem that protein is a macro that you’ve got free reign over with the keto diet, it’s not as simple as it might seem at first.
If too much protein is consumed, the protein can actually begin converting into glucose through a process called “gluconeogenesis.”
For people not doing keto, this can be a good thing. Not only do you have a lot of protein to maximize gains, but the extra protein can also provide the glucose necessary to power your workouts. However, things don’t look as cheery for people doing keto.
If your body ends up having too much glucose (whether it’s from carbs or from protein), it can be kicked out of ketosis. That’s why it’s best to spread out your protein intake throughout the day, rather than eating it in one sitting to avoid spikes. Furthermore, consuming protein close to a workout is a good way to make sure that your muscles recover.
Carbs are the evil macro when considering ketosis, but that doesn’t mean they’re entirely ignored in a diet. The standard recommendation for carb intake when doing keto is anywhere from 20 to 35 grams per day. However, if you’re very active or are still looking for gains, then that’s probably not going to cut if for you.
While you do want to prevent insulin spikes throughout the day, having an active lifestyle will most likely not significantly affect your state of ketosis. And especially if you’re still not wanting to leave any gains on the table, it might be a good idea to go up to 50 grams per day.
The rest, about 70% of your diet, is fat. But the trick with working out while on a ketogenic diet is managing how you eat each of these macros. Specifically, eating enough fat and eating carbs at the right times.
The “standard” ketogenic diet (SKD) is just that—standard. It has individuals sticking to under 50 grams of carbs each day, and that’s about it. However, the timing can be played around with in order to create the targeted ketogenic diet (TKD).
The TKD relies on timing your carb intake to either be right before a workout, or both right before and immediately after.
This can look like eating anywhere from 15 to 30 grams of carbs within 30 minutes before starting a workout, and then within 30 minutes after finishing your workout. The idea is that your body will use all of the glucose as it enters your bloodstream, and you’ll get a boost of energy to boot. It should also be mentioned that fast-acting carbs are preferred. This includes things such as fruits.
It’s also important to stick to the time frame in order for the carbs to be used up during the workout. The rest of your day can follow the standard keto dieting ratios—it’s just that time frame around exertion that’s important to follow.
Furthermore, this isn’t necessarily something you need to follow to a T if you mostly stick to flexibility or aerobic exercises.
The above is more-so geared for those looking to weight lift or even do high-intensity interval training—that’s where bursts of energy are needed, and something that the standard keto diet isn’t well suited for.
This is another variation of the standard keto diet that consists of anywhere from 5 to 6 days of sticking to a strict keto diet, and then “refeeding” for those other 1 or 2 days per week.
What this does is replenish the glycogen in your body’s tissue, rather than just the bloodstream. What does that mean? You’re effectively able to workout at a higher intensity on certain days, while also allowing for weight control and body composition control for the other days.
Refeed days should look something like this:
Quite the switch up, isn’t it?
While carbs are the name of the game on refeed days, you’ll still want to place a major focus on high-quality carbs. This includes things such as:
It might be tempting to dig into the cake and pizza, but save that for the cheat meals rather than the refeed days.
After the refeed, it’s best to try to enter ketosis as fast as possible once again. A lot of people intermittently fast to get to this stage—a popular plan being a 16 hour fast throughout the day with an 8-hour feeding window.
High-intensity workouts such as weight training are also advised. You’re going to be brimming with glucose, and you want to put it to work for maximizing gains and getting it out of your system. Hitting the barbell hard is the best way to do that—plus, your exercise performance won’t be hindered.
We’ve mentioned this several times now, but it’s worth saying again: the beginning of ketosis can potentially be rough. Therefore, it’s not advised to throw yourself to the wolves right off the bat. Do the things you’re comfortable with, and stick to steady-state aerobic exercises for the most part. However, that doesn’t mean you shoulder beat around the bush forever.
In the transition phases, it’s still important to do slow and steady workouts. For example, rowing, biking, or just walking are all good options—at least at the beginning.
Even things like stretching or stability work can get you moving and transitioning into ketosis more smoothly.
While you might be keen to hit the squat rack, high-intensity exercises like that can just make your keto flu symptoms worse, and potentially put you off of it entirely. You should definitely 100% not be trying for a new PR—that much is clear.
However, after a few weeks and depending on your body and experience level, you should be back up to snuff for the most part. While your top-level physical performance might suffer, you might not realize it at all depending on how intensely you work out regularly anyway. The important bit is to keep your eye on the prize and don’t give up before you reach it.
While the macros of the ketogenic diet have been outlined above, it’s just as important to keep in mind that you’re eating enough.
It’s very easy to under-eat when you’re doing keto. And it’s super important not to under-eat, especially right before a workout.
The keto diet is essentially limiting an entire food group out of your diet (carbs), so it’s usually just a matter of fact that one’s calories are also cut when switching over to the keto diet. And to add to that, ketosis often has a hunger-suppressing effect on people, which will further limit how much you’re eating.
This is not good—especially if you’re still trying to maintain muscle mass. The key is to pay close attention to your macros and make sure that you’re eating enough, even if you “feel” that you are. Not only will you feel bad after not eating enough before a workout, but your athletic performance will suffer as well.
And to add to the above: eating enough isn’t “enough”.
It’s crucial that you’re eating enough fat specifically. If you ignore the fat, then the diet basically becomes an Atkins diet, where carbs and fats are limited in lieu of protein.
This is a one-way ticket to lethargy, made even worse by the fact that you’re trying to stay as active as possible in the gym. Not to mention that the tiredness will be met with lost gains.
It really is super important to make up for all of the missing carbs with enough fat. Without eating enough fat from healthy sources (such as grass-fed meats, avocado, and fish), your body isn’t going to have enough energy to function and you’re not going to be able to maintain ketosis. That’s not even bringing up the mental drain that will come along with constantly being hungry. And if you’re trying to do high-intensity workouts too? Forget it.
Yeah, we’ve just spent a lot of words telling you how difficult it is to strike the perfect balance between keto and high-intensity workouts, but it’s really not all like that.
There are some great benefits if you stick with it and get into the groove slow and steady.
The big thing is the ability to change your body’s composition—specifically when it comes to your weight loss and fat-burning potential. Put moderate aerobic activity together with a body that’s primed to burn fat as its primary energy source, and you’ve got a recipe for a shredded physique. Chiseling that marble statue with perfect proportions is going to come easier than ever if you’ve got the grit to stick to the plan.
Stick to a targeted keto diet, and it’ll be much easier to build muscle while still maintaining some level of fat loss.
All in all, working out at a high level on the keto diet is just like working out on a regular diet. There are several things to consider in order to maximize performance and leave no gains behind—but in the end, it all comes down to sticking to a plan and seeing it through to your goals.