Making a change to a low carb / high fat diet is not all rainbows and roses! Like with most changes in your diet, there are some not so fun effects to your body.
Here are some of the most common issues (yes, I have gone through all of them and this is how I have moved past them).
Induction Flu - Headache, tiredness, nausea, confusion, brain fog, irritability
These are just a few of the side-effect. Here is a link to a great article on all-- and details on how to get past them. www.dietdoctor.com/low-carb/side-effects
The end results are completely worth a few discomforts that you have to push through.