It usually takes three to four days for your body to enter a state of ketosis because you have to use up your stores of glucose, which is sugar, in the first place. Any major change in diet can cause some problems, and there are patients who complain of IBS-like symptoms and feel overwhelmed at the start of the diet. (Fatigue occurs because you have less access to carbohydrates, which give you quick energy)
These issues may be part of the so-called “keto flu.” Other side effects of the keto diet, all of which involve avoiding carbs, can include dizziness, nausea, brain fog, cramps and headaches, and fatigue. Luckily, the keto flu usually lasts no more than a week—coincidentally, when people start to see the number on the thermometer drop.
In addition to the typical keto flu complaints, common side effects of the keto diet are diarrhea and "keto breath."
While, yes, diarrhea can be another symptom of the keto flu, it can also be related to how your body processes fat in particular (and as you know, the keto diet is full of fat). Reason: Some people just don't digest fat the way they should.
On the other hand, keto breathing is less of a side effect and more of a harmless inconvenience (your breath literally smells like nail polish remover). Basically, when your body breaks down all the excess fat on a keto diet, it produces ketones, one of which is the chemical acetone. (Yes, the same as nail polish remover.)
Your body then gets rid of these chemicals through urination, defecation, and breathing. Keto breath should stop once your body gets used to the diet, but in the meantime, pay special attention to oral hygiene.
