In my experience, the vast majority of people are adapted to burning carbs as their primary fuel, as opposed to burning fat. One of the most effective strategies I know of to become a fat burner is to restrict your eating to within a six- to eight- hour window, which means you’re fasting for about 16-18 hours each day. This upregulates the enzymes that are designed to burn fat as a fuel, and downregulates the glucose enzymes. This kind of intermittent fasting plan can be a useful modality to help you make the transition to a ketogenic diet.“That’s the way it started in the clinic for children with epilepsy. Basically, the child is given a 24-hour and sometimes 48-hour fast – water only. And then the ketogenic diet is introduced in relatively measured and small amounts,” Dr. Seyfried says.“Your body transitions naturally that way. Intermittent fasting is actually a very strong component of the approach. A three-day fast is uncomfortable, but it’s certainly doable. It gets your body into a new metabolic state, and then you can apply these therapies. The hardest part, I think, of this fasting is the first three to four days, depending on the individual and how many times they’ve done this.That’s basically trying to break your addiction to glucose. The removal of glucose from the brain elicits the same kind of problems or events as you would if you were addicted to drugs, alcohol, or something like this. You get malaise, headaches, nausea, lightheadedness. You get all the kinds of physiological effects that you would get from withdrawal of any addicting substance. I look at glucose as an addictive substance. It’s an addictive metabolite. Your brain is comforted by having glucose; your body is comforted. And when you break that glucose addiction, you have these particular feelings.... Fasting certainly has remarkable health benefits to the body: strengthening the mitochondria network system within the cells of your body. As long as the mitochondria of your cells remain healthy and functional, it’s very unlikely that cancer can develop under these particular states.”Unless you have a very serious disease, I believe it is best for most people to implement intermittent fasting slowly over six to eight weeks rather than a three day complete fast. You begin by not eating for three hours before you go to bed, and then gradually extend the time you eat breakfast until you have skipped breakfast entirely and your first meal of the day is at lunch time.
Of course you are only consuming non-starchy vegetables for carbs, low to moderate protein and high quality fats. One of the things I’ve noticed is that once you’ve made the transition from burning carbs to burning fat as your primary fuel, the desire for junk foods and sugar just disappears like magic.