Are you thinking of doing a fat fast on the keto diet? Here’s what you should know about the types of foods to eat and avoid, how to plan meals during the day, and the benefits and drawbacks before giving it a go. And of course, always consult with your physician first to get the green light.

If you’re struggling to lose weight you might try fasting as an approach. A fat fast is particularly appealing as you are eating mostly fats and can trick your body into ketosis where it burns fat and helps you shed pounds. By ditching carbs, you’re using fat for fuel in order to burn off that fat, and you will get results faster. Not sure how it works? Here’s a guide.

What Is Fat Fasting?

If you’re starting the keto diet, you might want to get a little push to lose initial weight, and you may try a fat fast, which is where you fast by eating only between 1,000-1,200 calories a day for three days of the week. This type of eating is very restrictive and should only last for a few days max, rather than becoming a permanent style of eating for the long-term. It is also a variation of keto, as 80-90 percent of calories are coming from fat, so your body goes into ketosis during the fast as well. And studies show that fasting can lead to rapid weight loss 1.

You can do it for 2-5 days, but never go over 5. And doing just 3 is a good middle mark. If you go longer than 5, your body will go into starvation mode and hold onto fat. As for meals, you would eat those 1000-1200 calories a day and make that come to about 4 or 5 meals a day, with 200-250 calories per meal.

And once you finish you can then go into a keto diet, where you increase your calorie intake but keep the carbs down and continue eating more high-fat foods. It is important to continue a keto diet after, just with more calories, since that initial weight loss is mostly water weight and you will gain it back if you begin adding more glycogen (from carbs) in your diet. If you’re looking to try a fat fast, here’s what to know before starting out. And consult with your doctor and dietitian first for help with the transition.

Benefits of Fat Fasting

The greatest benefits is that your body goes into lipolysis, which is where it uses fat to burn fat, rather than uses glucose from high-sugar, high-carb foods. And if it did, then excess protein you’d be eating would be stored as fat, rather than burned off more effectively. By doing this short-term fast for a few days, you are getting a jumpstart on weight loss to be achieved with more long-term keto. It gets that water weight off so you can dig deeper into fat stores and continue to get more fit and well.

Foods to Eat and Avoid During a Fat Fast?

If you are doing a fat fast, you should eat high-fat foods, like butter, oil, avocado, high-fat dairy, nuts and nut butter, fatty fish like salmon and tuna, and plenty of greens, such as leafy greens, broccoli, brussels sprouts, and other non-starchy veggies.

You also want protein, which you eat in moderation and can add flavor and calories. Just add fat to that protein, like putting butter on steak, avocado on grilled chicken, or mayonnaise on deviled eggs. These proteins are beef, eggs, chicken, fish, turkey, nuts and seeds. You might also have keto snacks on hand like fat bombs, which can be sweet or savory and pack in those fats with few carbs.

What Is a Fat Fast

As for what to avoid on a fat fast, you avoid starchy veggies, baked goods that are not keto, low-fat dairy, grains and bread, sugary items and beverages, beans, pulses and legumes, certain condiments like ketchup or sugary dressings, and most fruits (you can eat berries in moderation on keto). Basically if there is sugar or carbs, ditch it and go for something fattening instead.

Fat Fasting Sample Meal Plan

Here is a sample meal plan, where you fast for five days max.



  • One 8 oz. block of cream cheese (to enjoy all day long)
  • A cup of coffee with 2 1/2 tbsp. coconut oil, where you’d break this down however you feel more meals of the day.




How to Fat Fast the Right Way

If you are fasting then follow the structure for meal plans (200-250 calories and 4-5 meals a day) and do not go over five days max. Plus, drink plenty of water to stay hydrated, since dehydration can be a side effect of keto too. Keep a journal perhaps to take note of how you feel. If you feel sick at any point, then stop the fat fast.

Fat Fasting Drawbacks

A drawback is that it is super restrictive, which can be hard to deal with for someone who doesn’t like structure. Plus, if you are eating too few calories your body might begin to starve and you won’t lose weight but store fat instead, and your metabolism will be lower. Yet, the main drawback is if you go over the recommended period of doing the fat fast. So, if you go over five days, then you will get this side effect and calorie deficit that can be bad for your body and health long-term.

Is Fat Fasting for Everyone?

No, it is not. It can be good for someone who likes a quick detox and has willpower for it, but if you are worried about counting calories and feel fatigued, dizzy or sick, then you should stop the fat fast and speak to your doctor.


The fat fast might be a good option for a kickstart, but it depends on the person. Give it a shot and see if you’re curious, but do so the right way.


  1. NCBI. Intermittent fasting and weight loss. 2020 February -

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