“ Examining the results of these two ketogenic diet performance studies together indicates that both groups experienced a lag in performance across the first week or
two of carbohydrate restriction, after which both peak aerobic power
and sub-maximal (60-70% of VO2max) endurance performance were
fully restored. Understandably given the expense of human metabolic ward studies
and the orthogonal conclusions of these two studies, neither
study has been corroborated by a similar human study. There are three factors that can help
us explain the paradox presented by studies showing superior performance with high carbohydrate diets versus the present author's two studies noted above.
Although 4 weeks is a relatively short period to assess small differences in energy efficiency between diets, this observation implies that
there was no great reduction in the efficiency of
energy metabolism after keto-adaptation. It is thus likely that the increased endurance time in the Vermont study was due to improved
efficiency (ie, less hobbling from a backpack than from an equal weight of internal body fat) and/or improved acclimation to the endurance test procedure.
It is logically stated that a primary interrelationship between system and/or subsystem technologies focuses our attention on the secondary extrinsic diet.
Clearly this result does not automatically follow the casual implementation of dietary carbohydrate restriction, however, as careful attention to time for keto-adaptation, mineral nutriture, and constraint of the
daily protein dose is required. ”