dangerous levels of ketones in the bloodstream. Alcohol may affect ketone body production in the
liver and alcohol itself can be converted to ketones. As well, the production of ketones from
alcohol tends to result in less fat loss since less FFA is converted to ketones.
Strictly speaking there is no reason that small amounts of alcohol cannot be consumed
during a ketogenic diet although it should be realized that fat loss will be slowed. Additionally,
anecdotal reports suggest that alcohol may affect individuals more (in terms of drunkenness,
etc.) when they are in ketosis versus when they are not. Care should be taken by anyone
consuming alcohol.
Caffeine
Although caffeine is discussed in more detail in the supplement chapter, its potential
effects on ketosis are addressed here. A popular idea floating around states that caffeine raises
insulin levels which might possibly disrupt ketosis. As well many individuals find that some
caffeine containing drinks, such as diet soda, can interrupt ketosis.
However, this is contradictory to the known effects of caffeine ingestion, which are to raise
levels of adrenaline and noradrenaline and raise FFA levels. The only way that caffeine could
raise insulin would be indirectly. By raising adrenaline and noradrenaline levels, caffeine might
cause liver glycogen to be broken down into glucose and released into the bloodstream, raising
insulin. This would only occur prior to ketosis being established, such as after the carb-load
phase of the CKD, and would help a dieter to establish ketosis.
Citric acid and aspartame
In all likelihood, problems with diet soda relate to one of these two compounds, both of
which are used as artificial sweeteners in diet products. Citric acid may inhibit ketosis and diet
sodas containing citric acid or aspartame are not allowed for epileptic children on the ketogenic
diet (14). However, there is some debate over this point (15). Possibly, citric acid might affect
ketosis by affecting liver metabolism, primarily the Krebs cycle. Some individuals report that
citric acid prevents them from entering ketosis but does not affect ketosis once it has been
established. One study, examining very-low-calorie diets, found that the consumption of citric
acid inhibited ketosis and increased appetite in many individuals (16). Ultimately, individuals will
have to determine for themselves whether citric acid or aspartame has any effect on ketosis,
appetite or fat loss on a ketogenic diet.
Fiber
While fiber has already been discussed in terms of its effects on constipation in chapter 7,
there is some concern that fiber may negatively impact ketosis. Strictly speaking fiber is a
carbohydrate. However, humans do not have the enzymes necessary to digest fiber and derive
any carbohydrate grams or calories from it. Therefore, fiber intake should not be counted as part
of the total daily carbohydrate grams consumed on a ketogenic diet.