It's really the carbs. like breads and potatoes etc that you have to keep away from - as they keep the glucose levels higher and your system doesn't go searching the reserves kept in body fat. When it does, from what I've read and seen on YouTube from experts (scientific medical researchers, also doing it themselves), the energy burned is said to be of a higher quality and can fulfill many other functions, like cell replacement in the brain and elsewhere more rigorously than when it's glucose. Go and check it out on You Tube. There are good presenters but also some younger Yankee males who swagger it out too much for my taste.