Everyone varies. It can be a few days or a few weeks. I'm just back to my usual since Sunday after 3 weeks of holidays (I never eat wheat but had all the wine, dairy, sugar and starches!) and only started feeling a bit better yesterday. I'm still not very energetic yet though.

If the sluggishness persists you may need to assess the macros and try something different. I assume that you are eating adequate healthy fats and protein? Contrary to the experience of some others, I am usually more energetic on a very low carb version of this lifestyle but that may not be the same for you. In that case you might want to try adding some more starchy veggies (ie sweet potato, squashes, etc) and see if there is improvement.

Welcome iamdanielstro, Generally we do 50 to 60 fat and 20 to 30 carbs with the leftover for proteins. The sluggishness is variable with each person, some do not even experience it, for me it lated about a week. I am sending a friend request.

Thank you! out of curiosity what % of fat/protein/carb do you find works for you?

I'm strongly in the ketogenic camp of Primal/Paleo but that isn't for everyone by any means. So my macros may not be applicable to you.

When I started out I was 75% fat, 20% protein, and 5% carbs roughly. Now I aim for 60% fat, 30% protein, 10% carbs. I'm working into more intuitive eating so I have much variation. I like my carbs low because otherwise I'm craving, hungry all the time, and prone to bingeing.

Personally, I think fat and proteins should be the focus/majority of calories and fill in the rest with vegetables (carbs). Even with fat and protein being most of your calories your plate of food should still be mostly veggies.