especially important role as high levels of insulin appear to decrease protein synthesis (33,34).
The availability of sufficient amino acids is paramount for growth, and high levels of amino acids
increase protein synthesis (33,34).
A recap of the lowcarb week
Recall from previous chapters that the ketogenic part of the CKD lowers insulin and
thyroid levels, while raising glucagon. The data on GH is less clear, with some studies showing an
increase, others a decrease. The effects of the ketogenic diet on testosterone and cortisol are less
established. Thus, the overall effect of the ketogenic phase is a catabolic one, although ketosis
appears to be selectively catabolic (i.e. the protein sparing effect of ketosis).
Also recall from chapter 5 that the status of the liver is one of the key regulatory
processes in determining the anabolic or catabolic state of the body. Therefore, the first step in
maximizing any anabolic processes is to reverse liver metabolism from catabolic to anabolic.
Reversing the liver’s metabolic state
To optimize any anabolic processes following the training session immediately prior to the
carb-up, it is necessary to start before the workout itself. Changing the metabolism of the liver
from catabolic to anabolic requires two things: that the enzyme levels for glucose utilization are
returned to normal and that liver glycogen is refilled.
During long-term carbohydrate restriction, the liver enzymes responsible for metabolizing
carbohydrate decrease as discussed in chapter 7. During refeeding, it takes approximately 5
hours for liver enzymes to return to normal levels (35). Therefore, the start of the carb-up should
begin 5 hours prior to the final workout. It is unclear whether glucose, fructose, or some
combination of foods is ideal at the time. A good place to begin experimenting might be with 25 to
50 grams of total carbohydrate and 25 grams of protein. Dieter’s may wish to add a small
amount of unsaturated fats to this meal, to avoid an insulin spike.
Refilling of liver glycogen will shut down ketone body formation and shift the liver back
towards anabolism. For reasons discussed in Chapter 10 (the TKD), dietary glucose is not used
efficiently to resynthesize liver glycogen (36). Although no data on humans exists, due to
difficulty in performing the studies, the effect of various nutrients on liver glycogen metabolism
has been studied in rat livers which were removed from the animal (37).
This study found that glucose by itself refilled liver glycogen poorly, as expected. However,
the combination of glucose and fructose was much more effective. The highest level of liver
glycogen was found when glucose, fructose and glutamine (discussed in detail in chapter 33) were
provided. It took approximately 2 hours to reverse liver metabolism (37). Therefore, 2 hours
prior to the final carb-up, a combination of glucose and fructose (such as fruit) should be
consumed. Individuals may wish to add glutamine as well to see if it has an added effect. It
should be noted that some individuals find it more difficult to reestablish ketosis during the next
weekly cycle if they use glutamine during the carb-load.