Further to previous answers, I found this on a web search:
EFFECTS OF KETOSIS
Ketosis creates a measurable amount of acetone in the mouth. (Remedial measure: brush teeth and mouth with baking soda, increase water intake, eat vegetables)
Ketosis decreases aspartate in the brain, but glutamate and glutamine remain unchanged with increase in glutamate conversion to GABA. (GABA controls nerve cells in brain from firing too fast. Same effect as when taking Valium). Utilization of neutral amino acids to increase glutamine.
3. 10% will have trouble reaching ketosis
4. 21% will have an intolerance of the rapid onset of ketosis
5. 41% will become constipated (Remedial measure: increase fiber intake)
6. 47% will experience hypoglycaemia (symptoms: fatigue, weakness, confusion, dizziness, irritability, a rapid heartbeat, anxiety, sweating, trembling, hunger, and headaches i.e. withdrawal symptoms from sugar addiction.)
7. 16% will refuse to drink fluids (which are critical to deter acid build-up during ketosis)
8. 16% will experience lack of appetite (this is good if you are on a weight loss diet)
9. 26% will have nausea and vomiting
10. 65% will have a rise in total serum cholesterol (although HDL will increase proportionally)
11. 32% will have periods of anorexia (aversion to food)
12. 9% will have symptomatic metabolic acidosis when associated with infection
13.
9% will have carnitine insufficiency during early part of ketogenic diet (supplement with L-Carnitine)
14. 8% will have high levels of uric acid in the urine (Drink water, eat vegetables, neutralize with bases)
There are some refernces: here is the website:
Side-effects of Ketosis : LC Research/Media Forum : Active Low-Carber Forums
Looks like it wouldn't do any harm.