Low carbing will cause higher ketones in your blood. Some people are afraid of this because they confuse it with ketoacidosis, which is completely different.
Low carbing may cause "acetone breath". This might happen temporarily, or not at all. There is debate about whether it is caused by low carb per se, or some aspects of some low carb diets, eg high meat consumption.
LCHF is not a high protein diet. There are fears of kidney problems for high protein diets. However there is no evidence for these fears, with the exception of people who have existing kidney damage. And again LCHF is not a high protein diet.
Your step class is probably not the best place to get diabetic diet advice, particularly not for a non-mainstream diet like LCHF.