Ketogenic Diet, Weight Training & Glycogen Depletion
The Targeted Ketogenic Diet (TKD)
Having examined glycogen levels and glycogen depletion in the last chapter, the details of
the first ‘modified ketogenic diet’ can now be discussed. The targeted ketogenic diet (TKD) is
nothing more than the standard ketogenic diet (SKD) with carbohydrates consumed at specific
times around exercise. This means that the general guidelines for constructing a SKD in chapter
9 should be used with the exception that more carbohydrates are consumed on days when
exercise is performed. If fat loss is the goal, the number of calories consumed as carbohydrates
should be subtracted from total calories, meaning that less dietary fat is consumed on those
The TKD is based more on anecdotal experience than research. Invariably, individuals on
a SKD are unable to maintain a high training intensity for reasons discussed in chapters 18
through 20. However, for a variety of reasons,some dieters choose not to do the full 1-2 day carbup
of the CKD (discussed in the next chapter). The TKD is a compromise approach between the
SKD and the CKD. The TKD will allow individuals on a ketogenic diet to perform high intensity
activity (or aerobic exercise for long periods of time) without having to interrupt ketosis for long
periods of time.
Why pre-workout carbs?
Weight training is not generally limited by the availability of blood glucose. Studies giving
carbs prior to resistance training have not found an increase in performance (1). However,
almost without exception, individuals on a SKD who consume pre-workout carbs report improved
strength and endurance and an ability to maintain a higher intensity of training during their
workout. Anyone following a ketogenic diet who wishes to perform high intensity training can
benefit from the TKD approach.
Very little research has examined the effects of a ketogenic diet on weight training
performance and it is difficult to determine exactly why performance is improved with preworkout
carbs. It may be that raising blood glucose to normal levels, which only requires a
minimal 5 grams of carbohydrate (2), allows better muscle fiber recruitment during training or
prevent fatigue. Ultimately, the reason why carbohydrates improve performance is less critical
than the fact that they do.
Additionally, individuals performing extensive amounts of aerobic training on a SKD
typically report improved performance with carbs consumed before and during workouts. Even
at low intensities, performance on a SKD is limited by glucose and muscle glycogen. For this
reason, endurance athletes using a SKD are encouraged to experiment with carbohydrates
Amounts, types and timing of carbs
The major goal with pre-workout carbs is not necessarily to improve performance,
although that is a nice benefit. Primarily, the goal is to provide enough carbohydrate to promote
post-workout glycogen synthesis without interrupting ketosis for very long. That is, the
carbohydrate taken prior to one workout is really an attempt to ‘set up’ the body for better
performance at the next workout by maintaining glycogen levels.
Although experimentation is encouraged, most individuals find that 25-50 grams of
carbohydrates taken thirty minutes before a workout enhance performance. The type of
carbohydrate consumed pre-workout is not critical and individuals are encouraged to experiment
with different types of carbs. Most seem to prefer easily digestible carbohydrates, either liquids
or high Glycemic Index (GI) candies to avoid problems with stomach upset during training. A
wide variety of foods have been used prior to workouts: glucose polymers, Sweet Tarts, bagels,
and food bars; all result in improved performance.
One concern of many SKDers (especially those who are using a ketogenic diet to control
conditions such as hyperinsulinemia) is the potential insulin response from carbohydrate
ingestion on a TKD. Generally speaking, insulin levels decrease during exercise. Exercise training
itself improves insulin sensitivity as does glycogen depletion (3,4). So hyperinsulinemia should
not be a problem during exercise for individuals consuming carbs pre-workout.
However, following training, if blood glucose is still elevated, there may be an increase in
insulin (1). This has the potential to cause a hyperinsulinemic response in predisposed
individuals. Sadly there is no direct research to say that this will happen and the only data points
available are anecdotal. Most people appear to tolerate pre-workout carbohydrates quite well,
and very few have reported problems with an insulin or blood glucose rebound with post-workout
carbohydrates. Once again, for lack of any strict guidelines, experimentation is encouraged.
Effects on ketosis
Research suggests that carbohydrates consumed before or after exercise should not
negatively affect ketosis (5). However, some individuals find that they drop out of ketosis
transiently due to the ingestion of pre-workout carbohydrates. After workout, there will be a
short period where insulin is elevated and free fatty acid availability for ketone production is
decreased (5). However, as blood glucose is pushed into the muscles, insulin should drop again
allowing ketogenesis to resume within several hours. Performing some low intensity cardio to
lower insulin and increase blood levels of free fatty acids should help to more quickly reestablish
ketosis (see chapter 21 for more detail).
Post-workout carbohydrates might be expected to have a greater effect on ketosis, in that
insulin levels will most likely be higher than are seen with pre-workout carbohydrates (5,6). For
this reason, individuals may want to experiment with pre-workout carbohydrates first, only
adding post-workout carbohydrates if necessary.
Training and the TKD
While an intake of 25-50 grams of carbohydrates prior to training is a good rough guideline,
some individuals have asked how to calculate the exact amounts of carbohydrate which they
should consume around exercise.
For weight training, the amount of carbs needed will depend solely on the amount of
training being done. Recall from the previous sections that a set of weight training lasting 45
seconds will use approximately 15.7 mmol/kg of glycogen. Individuals on an SKD typically
maintain glycogen levels around 70 mmol/kg and performance will be extremely compromised if
glycogen is lowered to 40 mmol/kg, allowing roughly 2 sets per bodypart to be performed.
Assuming ~30 mmol/kg used per bodypart in 2 sets, we can estimate how much
carbohydrate is needed to replace that amount of glycogen. To convert mmol of glycogen to
grams of carbohydrate, we simply divide mmol by 5.56.
30 mmol/kg divided by 5.56 = ~5 grams of carbohydrates to replace 30 mmol of glycogen.
So for every 2 sets performed during weight training, 5 grams of carbs should be consumed
to replenish the glycogen used. If a large amount of training is being performed, necessitating a
large amount of carbohydrate (greater than 100 grams) it may be beneficial to split the total
amount of carbohydrate up, consuming half 30’ prior to the workout and the other half when the
workout begins. This should avoid problems with stomach upset during training. Some
individuals have also experimented with consuming carbohydrates during training. All
approaches seem to work effectively and experimentation is encouraged.
For individuals wishing to consume carbs post-training to help with recovery, an additional
25-50 grams of glucose or glucose polymers are recommended. In this situation, the type of
carbohydrate ingested does matter and fructose and sucrose should ideally be avoided, since they
may refill liver glycogen and risk interrupting ketone body formation. This limits post-workout
carbohydrates to glucose or glucose-polymers, which are not used to refill liver glycogen (7).
With pre-workout carbs, there will be an increase in insulin after training ends. Even if
individuals do not want to take in carbs after training, ingesting protein can help with recovery as
the insulin from pre-workout carbs should push amino acids into the muscle cells. Consuming 25-
50 grams of a high quality protein immediately after training may help with recovery.
Fat should generally be avoided in a post-workout meal. First and foremost, dietary fat will
slow digestion of protein and/or carbohydrate. Second, the consumption of dietary fat when
insulin levels are high may cause fat storage after training (1).
Summary of the guidelines for the TKD
1. Individuals following the SKD who want to perform high intensity activity will absolutely have
to consume carbs at some point around exercise. The basic guidelines for setting up a SKD (from
chapter 9) should still be used to develop a TKD. The only difference is that calories must be
adjusted to account for the carbohydrates being consumed around training.
2. The safest time to consume carbs, in terms of maintaining ketosis, is before a workout and
ketosis should be reestablished soon after training. Depending on total training volume, 25-50
grams of carbohydrates taken 30-60’ prior to training seems to be a good amount. The type of
carbohydrate is less critical for pre-workout carbs but quickly digested, high GI carbs seem to
work best to avoid stomach upset.
3. If more than 50 grams of carbohydrates must be consumed around training, it may be
beneficial to split the total amount, consuming half 30’ before training and the other half at the
beginning (or during) of the workout.
4. If post-workout carbohydrates are consumed, an additional 25-50 grams of glucose or glucose
polymers are recommended. Fructose and sucrose should be avoided as they can refill liver
glycogen and interrupt ketosis. Additionally protein can be added to the post-workout meal to
help with recovery. Dietary fat should be avoided since it will slow digestion and could lead to fat
storage when insulin levels are high.
5. If post-workout carbohydrates are not consumed, taking in protein only can still enhance
recovery as blood glucose and insulin should be slightly elevated from the consumption of preworkout
1. Conley M and Stone M. Carbohydrate ingestion/supplementation for resistance exercise and
training. Sports Med (1996) 21: 7-17.
2. Jacobs I. Lactate Muscle Glycogen and Exercise Performance in Man. Acta Physiol Scand
Supplementum (1981) 495: 3-27.
3. Kelley DE. The regulation of glucose uptake and oxidation during exercise. Int J Obesity (1995)
19 (Suppl. 3): S14-S17.
4. Ivy JL. Effects of elevated and exercise-reduced muscle glycogen levels on insulin sensitivity.
J Appl Physiol (1985) 59: 154-159.
5. Koeslag JH et al. Post-exercise ketosis in post-prandial exercise: effect of glucose and alanine
ingestion in humans. J Physiol (Lond). (1985) 358: 395-403.
6. Carlin JI et al. The effects of post-exercise glucose and alanine ingestion on plasma carnitine
and ketosis in humans. J Physiol (Lond). (1987) 390: 295-303.
7. McGarry JD et. al. From dietary glucose to liver glycogen: the full circle around. Ann Rev Nutr
I'm doing another 'carb-refeed' today, and was curious if the ingestion of carbs on these days PRE-workout would be beneficial. I ate icecream one evening and then killed it the next morning at the gym (sore for THREE DAYS!), so thought there might be a correlation (hopeful!) ??? I bought some icecream for my one carb refeed "treat" today, (low fat, rich chocolate organic goat's milk icecream! Only about 5 ingredients!) and had that with a banana this morning (prewo), considering that fructose/sucrose are not reccomended POST-workout. Sweet potatoes galore post-workout today... Anybody have a good sweet potato recipe by the way?! Tired of just roasting them plain...
Anyhow. Interesting read below, although I don't know HOW exactly they would determined "two sets" would equal x amount of glycogen being used. Wouldn't it depend on the intensity/weight?? Hmmmmmm
ALSO: sorry the text pasted all over the place. I can't find where I got the original article :-(
Interesting stuff. Thanks Jess.
I'm not sure if the pre-workout carbs really help performance or not. Personally, I haven't seen it, but I guess other have. I usually do 2 high-carb days back to back and often my first day (which is preceded by a lower carb day) I have better performance. I might give pre-workout a shot if my performance starts to suffer.
I made some sweet potato fries the other day. Slice them to desired thickness and coat with desired spices and roast at 400 for about 20 minutes, turning once or twice to minimize burning. I used garlic powder, cinnamon, cumin, cayenne, and chili powder. Weird combination, but tasted pretty good. They don't really get crispy like regular potatoes would. They're still pretty soft. But delicious.
Enjoyed reading that thanx
That wouldn't be Lyle McDonald's article would it? I know one of his books is on a ketogenic diet and he evolved new cyclical diets these days as well.
Yes, it's based off Lyle Mcdonald. I had about 100g or so of sugar this morning before my workout, and I was suuuuffering. I actually did better after eating just a little protein on the morning of lifting, proceeding the 50g of carbs in the icecream the previous evening. I'm not sure if it's just because I'm experiencing female issues today, if the icecream was too heavy, or if I just didn't get enough sleep. So many factors! Interesting, though!