What Is Zigzag method?
The International Sports sciences Association (ISSA) says, “The zigzag method of fat loss is a technique by where you vary the amount of calories you consume, in order to stimulate positive changes in your basal metabolic rate.” For losing fat, you might schedule several days where you consume a diet lower in calories than the maintenance level of calories you currently consume. You would then follow it up with a day where your calorie consumption would be above your maintenance level.
The ISSA provides a general explanation about the zigzag method, but I believe what Lyle McDonald, author of The ketogenic diet and many other famed fat loss books, says suffices. He says, “Probably has to do with re-feeds. The leaner you get, the more often you need to break your diet to keep it moving forwards. For example, if someone is trying to reduce body fat from 10 to 8 their body is fighting back much harder than the person going from 30% to 25% body fat. So while someone at 30% body fat may only be re-feeding once every 10 days, someone at 8% maybe re-feeding every 4th day to keep metabolism from shutting down too much.”
What Lyle says is that the re-feed day plays an important role in losing majority of the fat. How? During the free day/re-feed day you increase your caloric intake mainly carbohydrates (you can even consider cheating that day and eat your cheat meal—junk food—rich in calories). The increased caloric intake speeds up the slowing metabolism. Usually, during prolonged dieting the calorie restriction slows down the metabolic rate, and the best way to revert that is increase the metabolic rate is by consuming excess calories. However, note that in the beginning days or months the caloric restriction can help in fat loss. Also, the caloric restriction provides the right window to force the metabolism to slow down.
However, when it comes to re-feeds you can tweak it to your own benefit. For example, you can deplete carbohydrates for 3 days and load/re-feed the 4 day, or deplete carbohydrates for 5 days and load the 6th day. There are several ways you can experiment with it depending on its effectiveness. Also , the more fat you lose you will have to re-feed more frequently. On the flipside, the more fat you carry the more carbohydrate depleting days is executed.
Moreover when it comes to training—strength training days, usually deadlifting or squating that is usually you lift big weights on your re-feeding days. On the contrary, during the carbohydrate depleting days, you perform more of calorie burning work; wherein you might include HIIT drills or endurance work like running.
PS: The protein intake will remain the same, whatsoever. Remember that ample amount of protein is the prerequisite to fat loss.