the 3 phases of low-carb living part 2: fat adapted phase


In this second article of our series covering the 3 phases of becoming low-carb adapted, we will be looking at fat adaptation. (1)

Be sure to read part 1 on the honeymoon phase of the low-carb journey HERE.

Becoming fat-adapted is the main goal of eating a low-carb diet. You are quite literally adapting to a fat-based fuel source to run your body.

The honeymoon phase of low-carb living was focused on cutting the carbs out of your diet and burning off your body’s excess stored glucose to get into a ketogenic state. This next phase of low-carb living, known as fat-adaptation, is when your liver is made to create fat ketones as your energy source.

It typically takes the body 7 to 10 days to switch to a ketogenic state and to become fully fat-adapted. The fat adaptation phase lasts around 2 weeks for most new low-carb dieters (2).


Because this is the period of adjustment where your body must find a balance and get used to its new normal (3). There is a brief cross-over period where your body is creating ketones, burning off the last of its glucose stores, and trying to figure out how to handle your water, because ketosis acts as a diuretic and forces a lot of your fluids out.

Once the body has figured this all out and learned how to use these new ketones as efficiently as possible to run your systems, your body will become fully fat-adapted and ready to burn excess fats, and begin delivery the myriad of benefits that come from low-carb living (4).


The first thing that most people notice when in the fat adaption phase (5) is the massive decrease in hunger (6). Running on fat severely reduces the hormone ghrelin which is the chemical that tells your brain you’re hungry and need more food.

1. Obviously, not being hungry all the time is a wonderful tool in the fight against weight gain and helps tremendously in burning off the excess stored fat since calorie intake is kept lower.

2. Clearer thinking (7) and loss of the midday fuzzies is another mark of fat adaptation. It seems strange, but mental clarity is a huge benefit of becoming fat-adapted that many low-carb newcomers note as a welcome effect that they weren’t expecting.

3. Energy goes up, lethargy goes down. In the honeymoon phase, energy levels go up, but then come back down. In the fat adapted phase, raised energy levels become the new normal and can be counted on throughout the day.

In the fat-adapted phase you’ll see weight begin to drop off at a more normalized measure than the “whoosh” from phase 1 (8). It’s a slower loss at between a pound to 2 pounds per week, but it’s actual fat being burning off, not just water weight.


The potential pitfalls in the fat adaptation stage aren’t as severe as the honeymoon phase. By now, keto flu, dizziness, and the carb cravings should have subsided.

The fat adaptation phase is not without its frustrations.

  • That fat that was starting to come off, and those positive scale numbers… there’s a serious chance that they will stall (9). The reason for the stall goes back to the adjustments your body is finding with its new fuel source. Everything is put on hold while your internal mechanisms straighten everything out and get all of your metabolic parts on the same page.

  • Hardened stool is another short-term issue that can result from the fat adaption phase. All that protein, dairy, and fat can hit the bowels hard and make the stool just as hard.

  • Physical performance can dip during fat adaptation. This also relates to your body adjusting to the new fuel source.

But, like anything with low-carb, there are fixes.

More water is always a good idea for low-carb roadblocks. H2O keeps things moving and can be a huge help in getting things on track for optimal ketosis.

Exogenous Ketones are another potential helper. These are ketone supplements you can take to help with ketones in the system. Think of them as a fuel additive you give your system to give it the bump up it may need in the early goings.

Make sure your 20g daily carb allotment is used on low-carb approved veggies with lots of fiber and greens. Not getting enough fiber is usually why things get backed up and hardened in the opening stages of fat adaptation.

The important thing to remember with these pitfalls is not to let them knock you out of the low-carb lifestyle. Patience is key and will unlock the door to all of the low-carb benefits, but not if you get discouraged and stress eat a bag of chips.

Stay on the path. Contact us here at niKETO if you’re feeling the pull of temptation and need some encouragement.

Be sure to catch next week’s article about the Fully Adapted Keto phase.


(1) A Astrup B, Buemann P, Western S, Toubro A, Raben N, J Christensen. Obesity as an adaptation to a high-fat diet: evidence from a cross-sectional study. The American Journal of Clinical Nutrition, Volume 59, Issue 2, 1 February 1994, Pages 350–355.

(2) Juul Achten PhD Asker E Jeukendrup PhD. Optimizing fat oxidation through exercise and diet. NutritionVolume 20, Issues 7–8, July–August 2004, Pages 716-727

(3) Dr. David Ludwig. Adapting to Fat on a Low-Carb Diet. Feb 4, 2017. Accessed Sep. 24th, 2018.

(4) Natalie Olsen, RD, LD, ACSM EP-C. Why is the keto diet good for you? / Last reviewed Thu 31 August 2017. Accessed Sep. 24th, 2018.

(5) Hawley JA. Fat adaptation science: low-carbohydrate, high- fat diets to alter fuel utilization and promote training adaptation. Nestle Nutr Inst Workshop Ser. 2011;69:59-71; discussion 71-7. doi: 10.1159/000329283. Epub 2012 Jan 18.

(6) Gibson AA, Seimon RV, Lee CM, Ayre J, Franklin J, Markovic TP, Caterson ID, Sainsbury A. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Send toObes Rev. 2015 Jan;16(1):64-76. doi: 10.1111/obr.12230. Epub 2014 Nov 17.

(7) Tove Hallböök,a,* Sunggoan Ji,b Stuart Maudsley,b and Bronwen Martin. The effects of the ketogenic diet on behavior and cognition. Epilepsy Res. Author manuscript; available in PMC 2014 Jul 27.Published in final edited form as:Epilepsy Res. 2012 Jul; 100(3): 304–309.Published online 2011 Aug 27.

(8) Donald K. Layman Richard A. Boileau Donna J. Erickson. A Reduced Ratio of Dietary Carbohydrate to Protein Improves Body Composition and Blood Lipid Profiles during Weight Loss in Adult Women. he Journal of Nutrition, Volume 133, Issue 2, 1 February 2003, Pages 411–417.

(9) Mayo Clinic Staff. Getting past a weight-loss plateau. Published: Feb. 06, 2018. Accessed: Sep. @4th, 2018.


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