Using the Fat Fasting Technique

Updated Aug 30th, 2020 – Written by Craig Clarke

Medical review by Dr. Sarah Neidler, PhD

The fat fast is a technique brought by Dr. Atkins’ New Diet Revolution – used by people who are metabolically resistant and have trouble with their induction. Let me first say that fat fasting should be used in 2 situations and 2 situations only:

  • Breaking through a 2 week or longer plateau.
  • Inducing yourself into ketosis quicker, whether you are just starting keto or you had a cheat day.

It is important to stress that a fat fast should only be followed for a few days maximum as it does not provide sufficient protein and other nutrients. It is also not recommended when you are very slim and don’t have significant fat stores.

To be clear: You should not fat fast consistently. It is only for people starting a ketogenic diet and want to be inducted into ketosis faster, or for people that are on a long (2 weeks or more) plateau.


Understanding the Fat Fast

The lack of carbohydrates and protein will allow your body to depreciate your glycogen stores quicker, also allowing your body to go after the fat stores, like we want it to, to use as fuel.

Fat fasting will force the body to undergo lipolysis so that it burns up fat that is stored in the body.

Lipolysis is a process involved in the breakdown of fats, converting triglycerides into glycerol and free fatty acids. The longer you fast, the more of these free fatty acids will be released. Why is this important? Well, fatty acids are used by the liver to create small amounts of ketone bodies and used as fuel.

Lipolysis cannot happen if there is a significant amount of glucose coming in, but since 80% – 90% of what you will be eating are fats, you don’t need to worry about excess protein or carbs converting into glucose.


What is Fat Fasting?

What is Fat Fasting?

So, what exactly is a fat fast? It’s eating between 1000 and 1200 calories a day, where between 80% and 90% of your calories come from fat, and fat alone. You break these 1000-1200 calories into 4 or 5 meals a day, eating in blocks of 200-250 calories per meal.

It is normally done for 2-4 days but is never recommended to go for more than 5 days. Going longer than this will start to put your body in a real “starvation mode” and your muscle mass will begin to be metabolized as energy at a faster rate – the exact opposite of what you want.

Hungry? You most likely will be at first, but once your body starts adapting to the way you are eating, you will notice a drop in your hunger. This is because you will be eating your meals in frequent intervals with high amounts of fat, which increases satiety levels.

If you’re doing a fat fast, I recommend doing a 3 day fast. This normally drops about 5-8 pounds of body fat and water weight. When you enter back into a normal diet, expect to put back 2-3 pounds of that weight.


Should You Do a Fat Fast? The Potential Benefits

The fat fasting technique is essentially an accelerated version of the keto diet. This is because it requires you to restrict calories, carbs, and protein to lower levels than you would with a long-term ketogenic approach.

By eating in this way for a few days, you can speed up the pace of experiencing the benefits of keto, including:

  • Rapid weight loss. The combination of carb and calorie restriction usually leads to a weight loss of 1-2 pounds per day (of body fat + water weight).
  • Breaking through weight loss plateaus. If you have been experiencing a weight loss stall for two weeks or longer, following a fat fast may be an effective strategy. To learn more about how to bust through plateaus on keto, follow this link.
  • Increasing ketone levels. Whether you are transitioning into ketosis or trying to achieve deeper levels of ketosis, fat fasting is one of the fastest ways to do this.

However, as with other highly restrictive weight loss approaches, the fat fast can come with a few downsides as well. This is why it is not recommended nor sustainable for long-term dieting.


What are the Side Effects? Fat Fast Drawbacks

Along with the potential for rapid weight loss and ketosis, the fat fast can come with a few side effects. The most common drawback is called the “keto flu” — a collection of flu-like symptoms that we may experience as we adapt to the keto diet.

Fortunately, there are a few simple ways to remedy these symptoms, such as maintaining proper hydration, increasing electrolyte intake, and taking MCT oil. To learn more about the keto flu and how to avoid it, follow this link.

Other than the keto flu, the fat fasting technique can also cause rapid fluctuations in blood sugar, blood pressure, hormones, and weight. For this reason, it is best for anyone who has diabetes, heart disease, endocrine-related issues, or an eating disorder to consult with their healthcare practitioner before implementing a fat fast.


What to Eat

So let’s get to it. What should you be eating? That’s up to you.

There’s not all that much choice you have, as you have to keep the calories relatively low and the fat very high. Try to aim for foods that are almost pure fat: avocado, macadamia nuts, cream cheese, fat bombs.

Feel free to mix meat in there, but be careful about the amount of meat you actually eat. As most of it will have a good amount of protein, you want to be sparing.

Chicken, tuna, turkey, bacon, prosciutto, etc. will be a nice addition to get a bit of protein in your system and add some extra flavor to your dishes.

What to eat on a fat fast.

Below, you can see some options for single meals:

  • 2 tablespoons of Raw Coconut Butter (this is blended coconut meat, not the same as coconut oil)
  • 1 serving of Spiced Bacon Deviled Eggs
  • 1-2 servings of your favorite Fat Bomb
  • 1 serving of Cheesy Creamed Spinach
  • 1 serving of Egg Salad Stuffed Avocado
  • ½ medium avocado mashed with 1 tbsp. of mayonnaise (home-made if possible)
  • 2 oz of mackerel, salmon or sardines (cooked or tinned) mashed with 2 tbsp. mayo (serve on 1-2 small lettuce leaves to make keto-friendly fish tacos)
  • ½ serving of Keto Mocha Mousse
  • 1 cup of Keto Proof Coffee
  • ½ cup of Iced Ketoproof Green Tea
  • 1 oz. Macadamia Nuts
  • Macadamia nut butter with 2 oz. cream cheese
  • 1 oz. chicken with 2 tbsp. mayonnaise
  • 2 egg yolks with 1 tbsp. mayonnaise
  • 1 cup Coffee with ¼ cup heavy cream
  • 4 slices bacon (be careful with this, as it dwindles under 80% calories from fat)
  • ¼ cup heavy cream whipped with Da Vinci Flavored Syrup
  • 2 oz. sour cream with ½ cup cucumber
  • ½ serving of sugar-free Jell-O with ½ cup whipped cream

Three Day Fat Fasting Meal Plan For Keto

Day 1

Day 1 Macronutrient Breakdown

  • Total Calories: 1,076
  • Total Carbs: 10.98 g
  • Net Carbs: 6.54 g
  • Total Protein: 30.76 g
  • Toal Fat: 102.59 g
  • Percentage of Calories from Fat: 85.8%

Day 2

Day 2 Macronutrient Breakdown

  • Total Calories: 1,036.95
  • Total Carbs: 17.39 g
  • Net Carbs:  10.79 g
  • Total Protein: 21.21 g
  • Toal Fat: 100.1 g
  • Percentage of Calories from Fat: 86.9%

Day 3

Day 3 Macronutrient Breakdown

  • Total Calories: 1,196.68
  • Total Carbs: 17.04 g
  • Net Carbs: 12.02 g
  • Total Protein: 40.33 g
  • Toal Fat: 110.39 g
  • Percentage of Calories from Fat: 83%

How to Implement The 3 Day Fat Fasting Meal Plan

By making the recipes in this meal plan, you’ll have plenty of extra servings that you can use to kick-start your regular ketogenic diet or extend your fat fast for another day or two. Feel free to substitute any fat bomb recipes for the fat bombs recommended in this meal plan (you can find some more fat bomb ideas here).

If you would rather keep your fat fast as easy as possible, then simply pick a couple suggestions from the list of suggestions above and eat between 1000 and 1200 calories of them during your fat fast. Just make sure you are getting 80- 90% of your calories coming from fat. You’ll find the perfect example of how to keep your fat fast as simple as possible below — no need for fat fasting meal plans or food prep.

How to Implement The 3 Day Fat Fasting Meal Plan


Making It Easy

If you’re unlike me and just love cream cheese, then you can snack on a full 8 oz. block of cream cheese for the day along with a cup of coffee with 2 1/2 tbsp. coconut oil in the morning.

A block of cream cheese with a ketoproof coffee is one of the best ways to do a fat fast, as it is:

  • 1020 Calories
  • 97g fat (86% calories from fat for the day)
  • 8g Carbs (3% calories from carbs for the day)
  • 16g Protein (6% calories from protein for the day)
  • Easy – one of the most important factors.

How to make a fat fast easy.


Key Takeaways for a Successful Fat Fast: Quick FAQs

Let’s trim the fat from the fat fast technique with these simple questions and answers. For more detail, scroll back up to the relevant section or click the links provided.

Who is the Fat Fast Helpful For?

Anyone who is looking to:

  • Enter deeper levels of ketosis quickly
  • Break their long-term weight loss stall

What are the Benefits and Side Effects?

The benefits include rapid weight loss and significantly higher ketone levels. The primary side effect is the keto flu (which you can learn how to remedy in our keto flu guide).

Who Shouldn’t Implement a Fat Fast?

Anyone with the following conditions should consult their healthcare practitioner before trying a fat fast:

  • Diabetes (type 1 or type 2)
  • Heart disease
  • An endocrine-related condition
  • An eating disorder

How Do I Follow a Fat Fast?

Follow these three rules:

  1. Eat around 1000 to 1200 calories a day
  2. 80-90% of those calories should come from fat
  3. Consume 4-5 meals a day with roughly 200-250 calories in each meal

For some fat fast meal ideas, check out the keto recipes and foods listed above.

What Should I Do After the Fat Fast?

The best way to maintain and build on your weight loss results is by following a sustainable and healthy diet for you.

To learn more, read through our guide to maintaining keto results for life.

Sources: