FAD, which stands for Fat Adapted Diet, is not an actual diet per se. It is a state in which your body becomes fat adapted and metabolically flexible. However, once you achieve fat adaptation, you still need to maintain a disciplined diet to a certain degree. It is easier to maintain your weight loss in a fat adapted state which is why the FAD may be the best “diet” ever.

What Does it Mean to be Fat Adapted?

Being fat adapted means that your body has reached a state where it burns fat, instead of glucose, as its main source of fuel. This means that you’re also metabolically flexible so you don’t always have to be on a strict diet like the ketogenic diet. You have the flexibility to eat more carbs and still maintain your fat adaptability. Of course, you want to make sure you’re primarily consuming healthy carbs and not unhealthy, processed carbs. Eating too many processed foods will eventually make you metabolically inflexible and lose your fat adaptability. The amount of carbs you can safely eat and still be fat adapted is different for everyone which I’ll cover later. Maintaining a fat adapted state is much easier than trying to become fat adapted.

For the purposes of this article, I will be implying that being fat adapted means having reached your optimal weight and metabolic flexibility. You can be fat adapted and still be in the process of losing weight(or fat). But if you’re not at your optimal weight, you are most likely not at your highest state of metabolic flexibility.

How Do You Become Fat Adapted?

The most popular method of becoming fat adapted is through the ketogenic diet. This fairly strict diet requires eating approximately 70% of your calories from healthy fats, 20% from proteins, and less than 10% from carbohydrates. Usually it takes 1 to 2 weeks to get your body into a constant state of ketosis. When this happens, your body produces ketones from the fatty acids in your liver. Your body uses these ketones as your main source of fuel. Depending on the individual, it can take anywhere from a few weeks to a few months or more to become fat adapted while on a ketogenic diet. Once you have reached fat adaptation, being in ketosis becomes less important.

One of the downsides of the ketogenic diet is that many people will experience what is coined the “keto flu”. Symptoms include fatigue, brain fog, headaches, nausea, constipation, diarrhea, and difficulty sleeping. This has deterred many from staying on the ketogenic diet.

Not everyone can go on the ketogenic diet. It is highly recommended to consult with a health professional before undergoing such a strict diet.

Modifying the Ketogenic Diet

Instead of going on a strict, ketogenic diet, an alternative would be to modify it by slightly increasing your carb intake and lowering your fat intake. Assuming your activity levels remain the same, this approach will take you longer to become fat adapted. But you should find this diet modification easier to manage especially if you enjoy eating carbs. You may also avoid getting the keto flu.

As a general rule of thumb, the more you increase your carb intake, the more you will need to increase your activity levels if you want to become fat adapted. How much you can increase your carbs depends on the individual but you should aim to keep it below 30% of your total calories. A good recommendation would be to only increase your carb intake on the days where your activity levels are high. So, it should be safe to eat more carbs if you plan on hiking 10 kms up a mountain.

If you’re having difficulty reaching fat adaption and also experiencing bloating, excessive gas, and/or constipation, you should consider taking a digestive enzyme. Make sure the digestive enzyme contains lipase which helps your body break down fats into fatty acids. Drinking plenty of water will also help improve the digestion of fats.

The Benefits of Being Fat Adapted

There are many benefits to being fat adapted. The most notable benefit is being able to lose weight and maintain that weight loss. As mentioned earlier, being fat adapted means you’re metabolically flexible. You can start eating more healthy carbs and even have a cheat day once in a while. Just be sure to follow your cheat days with a lower carb day. The amount of carbs you can safely eat without losing fat adaptability is different for everyone. It depends on a number of factors including activity levels, stress levels, quality of sleep, and toxic exposure.

Another benefit of being fat adapted is having reduced cravings for carbs. Eating a primarily higher fat diet results in higher satiety. You’ll be snacking less often which is better for your digestive system as it gives your body more time to rest and digest. As a result, you’ll most likely be spending less money on food which not only benefits your waistline but also your pocketbook.

Other reported benefits include an increase in energy, less fatigue, improved cognition and focus, better sleep, and quicker post-exercise recovery. If you’re a fat adapted, endurance performance athlete getting ready for a competition, loading up on some carbs before the competition can give you that extra edge. Your body will have that extra storage of glycogen to use as fuel during periods of intense exercise while your fat stores will be utilized for endurance. But you don’t need to be a competitive athlete to enjoy the benefits of increased endurance. Whether you go on a trail run, bike for 50 kilometers, or hike up a towering mountain, having all your fat stores available for fuel will make it that much easier.

Other measures I’ve made to maintain my fat adaptability include eliminating industrial seed oils and gluten from my diet, doing periodical detoxes/cleanses, and incorporating cold thermogenesis into my daily routine. There has been a growing consensus among those in the health and wellness field of the dangers of vegetable seed oils. A gluten free diet has been shown to reduce waist circumference in subjects with metabolic syndrome. Cold exposure has been shown in studies to increase your metabolism. There is conflicting information in the health and wellness industry regarding detoxes/cleanses. But if done right, they can greatly assist in ridding the body of toxins and harmful bacteria/parasites. For me, I notice an improvement in my gut health and digestion after doing it.

My Fat Adapted Maintenance Diet

The amount of carbs I consume to maintain my fat adaptability ranges from 30 to 50%. This means my fat consumption ranges from 30 to 50% as long as I consistently keep my intake of protein to around 20%. Since I am metabolically flexible, the days I consume more carbs than fats will not matter as long as the carbs are somewhat healthy and not overly processed. Over the course of a week, I do make it a priority to keep my healthy fat intake higher than my carbohydrate intake.

A recent modification of the ketogenic diet that is gaining in popularity is the cyclical ketogenic diet. This usually entails eating 5 to 6 days of a ketogenic diet followed by 1 to 2 days of a very high carb diet. I personally don’t find this appealing compared to my current diet mainly because of the strictness of the ketogenic diet. If I were to categorize my current diet I would consider it to be more of a modified Mediterranean diet than a modified ketogenic diet. Avocados, olive oil, seafood, eggs, grass-fed butter, vegetables(starchy and non-starchy), fruits, and even legumes and some grains are what comprise most of my diet. I try to keep my red meat(grass-fed) and poultry consumption to under 10% of my calories. In addition to intermittent fasting, I do a 24 hour fast at least once every two weeks.

My Fat Adapted Exercise Routine

Once I become fat adapted, my activity levels decrease around 20 to 30%. Why? Because I’ve reached metabolic flexibility and only need to maintain my weight instead of lose it. I also only need to maintain my muscle mass since I have no desire to get bulkier. Trying to lose weight(or fat), gain muscle, and reach fat adaptation is when you want to increase your activity levels.

In terms of my exercise routine, I generally do at least 60 minutes of resistance training per week spread out over 2 to 3 sessions. I try to do at least one HIIT session per week for at least 10 minutes. The most beneficial exercise I do daily is yoga. The length of my sessions range anywhere from 15 to 60 minutes. Other activities I participate in, depending on the weather, include hiking, trail running, tennis, paddle boarding, and snowboarding.

Conclusion

To summarize, I would describe the fat adapted diet as consisting of two phases, the initial phase and the maintenance phase. The initial phase is when you’re trying to lose weight(or fat). It involves going on a very low carb, high fat diet similar to the ketogenic diet. The maintenance phase is when you’ve reached your weight loss goal and are fat adapted. You have gained metabolic flexibility which allows for an increase in carb intake. Factors that affect your ability to stay in a fat adapted state include activity levels, stress levels, sleep quality, and if and how often you do intermittent fasting.

Based on the growing amount of supportive research and the number of people successfully adopting this approach, it is hard to argue against the merits of fat adaptation. Whether its weight loss, increased energy and endurance, better focus, or being able to maintain your weight loss, the immense benefits of being fat adapted are gaining acknowledgement. Being metabolically flexible and not having to always be on a strict diet is the main reason I believe that this FAD, or fat adapted diet, may be the best “diet” ever.

Sources

• Metabolic Flexibility as an Adaptation to Energy Resources and Requirements in Health and Disease
• Keto-Adaptation and Endurance Exercise Capacity, Fatigue Recovery…
• INTERMITTENT FASTING AND HUMAN METABOLIC HEALTH
• The Excessive Seed Oil Hypothesis: The More Seed Oil We Eat, The More Disease We Get
• The Effect of Gluten Free Diet on Components of Metabolic Syndrome: A Randomized Clinical Trial
• Ketogenic diets: Boon or bane?