The biggest trouble is still getting adequate levels of other nutrients, like protein and fat, so that you can keep your energy levels up while doing without your primary source of fuel. (blog.nkdnutrition.com)
To date, natural oil still serves as our primary source of fuel, even though a much cleaner alternative exists in the form of synthetic fuel. (sciencedaily.com)
Your body has to change its production rate of certain hormones and increase the production of enzymes which can transform stored fat into a primary source of fuel for the organism. (fitnessandpower.com)