Keto adaptation (aka fat adaptation) means your body is now accustomed to using ketones (fat) for energy, and no longer goes searching for carbohydrates (glucose).
People mistakenly think producing ketones means you’re keto-adapted. This is also a misconception among keto researchers who run trials on subjects after eating a low-carb diet for only few days or a few weeks (one of the main reasons why most keto research is complete garbage).
Even among the most elite athletes, it takes at least 3 months for your body to get used to burning fat for fuel. If you’re like me, slightly chunky and insulin resistant, it can take as much as 6 months to move into the keto adaptation phase. If you’re morbidly obese, don’t be surprised if the induction phase lasts as long as 9 months.
WHAT’S HAPPENING TO YOUR BODY
- Ketone production is now instantaneous: Your body now “instantly” produces ketones when glucose is not available. You no longer experience wild swings in blood glucose, and no longer get those crazy sugar cravings.
- You’ve developed ketone proficiency: A key sign of keto adaptation is that your body only produces the ketones it needs, and nothing more. So don’t be surprised if your blood ketone levels actually go down. This just indicates that your body is becoming more efficient.
- Your palate has changed significantly: Assuming you’re not eating tons of artificial sweeteners, your taste buds should be radically altered. After eating low-sugar for a few months, you can now taste the sweetness in a stick of celery or piece of broccoli. A handful of pistachios or cashews taste like candy. Berries are now super-sweet. A sample of “traditional” ice-cream or milk chocolate would be sickeningly sweet. You should also be more accustomed to eating all that extra salt, which can be difficult if you’ve eaten a low-salt diet for a long time.
WHAT TO EXPECT
Your body has now settled in to a new normal, and you should therefore expect a “normalization” of all the changes observed in Phase 2. Here are some of the more common signs that you’ve become keto-adapated:
- Urine keto strips no longer work, blood ketone levels drop: As noted above, your body now knows how much ketones to produce, and doesn’t make any extra. A drop in ketone levels is perfectly normal, and actually a positive sign.
- Weight loss slows, or stabilizes: Weight loss can be rapid when first transitioning into ketosis. A lot of that initial weight loss is water release, in response to lower glycogen levels. Once the water is gone, body fat starts being consumed, and the pounds continue to fall. Although results will vary greatly, you can expect the rate of weight loss to be cut in half once you’ve become keto-adapted (assuming you’re still in a calorie deficit). In my case, I lost 10% of my bodyweight in the first 6 months, but it would take a year to lose another 5%[1].
- Athletic performance returns to normal, and might even be better than before: If you participate in sports or any kind of training program, your body should be fully accustomed to burning fat for fuel at this point, and many people actually see an improvement in performance. If you weight train, you will likely see bigger strength gains[2], since keto diets prioritize fat over muscle loss (yes, you don’t need carbs to build muscle). If you’re an endurance athlete, you’ll notice you can run/bike/swim for longer without hitting the wall.
- Bulletproof immune system: Pre-keto, I was sick all the time, had pains everywhere, and seemed to be allergic to everything. This was due to chronic inflammation brought on by too many carbs, and a broken insulin-regulation system. Since going keto 5 years ago, I’ve only had the flu once, and very rarely get colds. If I get the sniffles, it might only be a day or so, or sometimes even for just a few hours. A few months of keto will allow your body to rebuild its immune system, eventually making you highly virus-resistant.
- Superhuman recovery: Another key indicator of keto adaptation is miraculous recovery rates. This includes recovery from strenuous workouts, as well as common injuries. I used to sprain my ankle all the time, which would sideline me for weeks. I now just shake it off, and move on like nothing happened. A tough workout at the gym would leave me really sore, and force me to take a few days off. I now train much harder than before, and can actually train the same body parts on consecutive days. A wrong move in the squat rack or deadlift platform still causes injury (usually back pain), but I’m always good to go in a few days. My ability to recover is almost superhuman, a sentiment echoed by many elite trainers, who use keto diets to increase workout capacity, and reduce dead time.
STOP AND THINK
This is the phase where you want to evaluate where you are, how far you’ve come, what’s improved and whether you’re headed in the right direction. This is also a good time to review and adjust your macros, especially if you’ve already lost a lot of weight.
Here are some key questions to ask yourself:
- How do you feel? Are you still getting cravings, still feeling weak when you haven’t eaten for a while, still feeling “hangry”? If this is the case, then you’re definitely not keto-adapted. In fact, you probably haven’t been consistently in ketosis for long enough. This can happen to people who do “loose” keto, on occasion, whenever they feel like it. Ketogenic diets don’t work that way. They need consistency, especially at the beginning. Take the time to measure what you eat, and see if you’re actually hitting your targets for the day.
- Are your energy levels back to normal? Assuming you’ve set the right carb and protein limits, then your daily energy requirements will come from your body fat and dietary fat. Getting too little dietary fat is just plain calorie restriction, and will make you feel very tired. Yes, you’ll lose a lot of weight, but usually at the cost of a slower metabolism. If you’re still lacking energy, slowly increase your fat intake, and see if things improve.
- Did you achieve your weight loss goal? If weight loss was the goal, then are you where you want to be? If so, you might want to switch to maintenance mode, which may mean eating more dietary fat so you don’t tap into your fat stores. Your “ideal” weight is specific to you, and only you. Don’t fall into the trap of trying to hit a BMI target, trying to fit into size zero jeans, or dropping body fat to 10%. Unless there’s a specific reason for extremely low body fat, find a weight that feels comfortable for you, and don’t follow the latest Instagram trends.
- Did your weight loss stall completely? More commonly, people complain they haven’t lost enough weight, and their weight loss has stalled. As your weight drops, your daily energy expenditures will also drop in tandem[3], so you may actually need fewer calories in a day. And that might mean lowering fat grams or even protein intake. Go back to the keto calculator, re-enter your weight and recalculate your macros. And above all, make sure you’re measuring what you eat, and not just guessing.
- Did you fix whatever problem you set out to solve? If you’re using keto to get healthier, did you achieve your goal? Did you fix your digestive problems, do you still get joint pain? Did your acne clear up, how are your allergies and headaches? Hopefully, you’ve been logging progress from the beginning, and hopefully, you’re seeing some improvement by now. If not, stop and re-evaluate. Go over your journals, see if there’s something you’ve missed or if there are any obvious patterns. Maybe you just haven’t given it enough time[4], or maybe you’re looking for the answers in the wrong place.
Now that you’re fully keto-adapted, you’ve reached the grand prize — full metabolic flexibility.
NOTES:
1 I considered myself to be chunky, but certainly not obese, therefore my weight loss was not dramatic. It’s also worth repeating, I switched to keto in hopes of curing my migraines, and not specifically aiming for weigh loss. My fat intake is much higher than if I were trying to lose weight.
2 The only exception would be athletes who participate in explosive sports, like karate or sprinting, which seem to require a small of pre-workout carbs, in the order of 10 to 15 grams. For more info, check out this interview with Nutritionist Alessandro Ferretti and Luis Villasenor over at Ketogains.
3 Keto calculators assume an average metabolism, and an estimate of calories burned during the day, which obviously is just a wild guess. If you’re carrying a lot of muscle, your metabolism will be higher. If you train heavy at the gym, you will burn more calories during the day, even at rest. If you don’t get enough calories and do long cardio sessions on the treadmill, your metabolism may be lower than normal. Use keto calculators as a starting point, but don’t be afraid to adjust. Listen to your body — it will tell you if it needs more or less fuel.
4 As previously noted, I transitioned to keto in order to get rid of my migraines, which at first seemed to be ineffective. It was only through reviewing my journals and more carefully tracking my migraines that I would notice patterns I hadn’t seen before. Although migraine frequency was not improved, severity and duration was much lower post-keto.