There is still a lot of debate about how best to get into ketosis when you first start the diet. You can read about how to get BACK into ketosis after a cheat day in “How can I get back into ketosis after a cheat day?”. There are three main ways to get into ketosis and each have good and bad points. Of course, many people choose to do a combination of the different strategies.
The first and simplest way (although arguably the hardest) is by fasting. After not eating for 2-4 days, you will be in ketosis and can start eating a normal keto diet. Fasting is not for everyone, and considering the time involved, it would be very difficult for most people.
This strategy burns through your carbohydrate reserves quickly, as it is the primary energy source. However, one of the reasons it is debated is that many people starting ketogenic diets using the next strategy still get into ketosis in around the same amount of time, so it is questionable as to how much fasting helped decrease the time to ketosis.
The second strategy is to just start the diet. Jump immediately into the high-fat diet keeping net carbs <20 per day. This is obviously easier for most people than to not eat at all for 2-4 days. That is the upside. However, for those first 2-4 days, you will be eating a lot of fat that isn’t converted to ketones until you are actively in ketosis.
During this time period, you are most likely storing the excess fat as body fat. Chances are, you won’t notice the increase for reasons discussed in the water weight section of “What happens to the body during keto?”, but it is good to be aware.
The third strategy is a slow induction into ketosis. Over the course of couple of days (or weeks), someone using this strategy will gradually increase the amount of fat while decreasing the amount of net carbs they eat. Supposedly, this decreases cravings and makes the transition to ketosis easier. On the other hand, it takes quite a bit longer to reach full ketosis.
Once you reach a certain point, usually when your main glycogen stores are almost gone, you will start to fluctuate in and out of ketosis. At this point, you should switch to a completely ketogenic diet.
There are multiple ways to combine the two strategies as well. The two most popular would be a short 12-24 hour fast followed by the Standard Keto Diet (or another ketogenic diet). Theoretically, this would help you burn through your carb stores quicker and get you eating food again earlier by not having to fast as long.
The second popular combination would be to start with a low carb, low fat diet, moderate protein diet for the first 2-3 days and then start increasing the amount of fat you eat over the next couple of days.
The thought behind this is that you get your body use to low carbs (without the added fat calories) and when your body starts running low on carbohydrate stores, you have started to increase the fat available for energy.
Until there is more research done in this area, we won’t know which strategy is most effective in reaching ketosis the shortest amount of time. You need to choose what will be best for you and go that route.
I personally can’t wean myself off carbs (third strategy), I have to go cold turkey. I’m either all-in with keto, having a cheat day (or two), or not on keto at all. Going back and forth is more stressful to me than just staying on the diet. Of course, I have the unfair advantage of KetoSavior™ too.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.