Unlike many of your standard diets, the high-fat, carb-free keto diet leaves little room for beloved cheat days. But what are you supposed to do when your cousin gets married, your best friend hosts a birthday brunch, or you just need a slice of pizza? We asked the experts about taking time off of keto, its effects on your body (and diet results), and how to bounce back fast.
Why Keto Differs From Other Diets
Unlike your typical clean-eating or low-carb diet, keto has the very specific goal: to shift your metabolism from relying on glucose (from carbs and sugar) for energy to relying on fat.
The process, which involves removing virtually all carbs from your diet—and depleting all of the stored carbs (called glycogen) in your body—takes time and dedication. Especially for those first few weeks and months.
Once you fully shift into fat-burning mode (called ketosis), benefits like fat loss, decreased inflammation, and improved energy start to kick in.
Issue is, even just one day (or one meal!) that’s too high in carbs can throw you out of ketosis, explains Will Cole, I.F.M.C.P., D.C., functional medicine practitioner and author of Ketotarian.
“For a keto diet to be truly successful, there can be no ‘off’ or ‘cheat’ days,” he says.
How Many Carbs Is Too Many Carbs?
Of course, though, sometimes life happens! There may be potatoes; there may be cake.
How much diverging from your usual keto eating plan affects ketosis—and your results—though, depends on just how far off the rails you go.
“Taking in a touch more carbs will probably lower your blood ketones slightly but still leave you in ketosis,” says Toby Amidor, M.S., R.D., C.D.N., author of Smart Meal Prep for Beginners. This low level of ketosis is known as ‘light ketosis.’
Just note that light ketosis does not yield the profound benefits—like weight loss and reduced cravings—people experience in ‘deep’ ketosis, when ketone levels are higher.
According to Cole, some people may be able to eat up to 100 grams of net carbs and still hold onto some level of light ketosis.
Stray farther into carb land, though, and you can expect to completely shift out of ketosis.
The Impact Of Off Days
If your off day involves carb-bombs like donuts and pizza and you shift out of ketosis, you’ll have to endure ‘keto flu’ symptoms all over again while transitioning back in later.
“If you go all-out on carbs, you won’t feel good,” Amidor says. “The fatigue, keto flu, hunger, and all the other symptoms you experienced while transitioning into ketosis can reemerge.”
Many people find that true off days throw off their digestion, appetite, and energy levels. They feel tired and lethargic, deal with some stomach upset and bloating, and notice old cravings return.
In the long run, off days can seriously mess with your keto progress.
If you’re constantly shifting in and out of true ketosis, you prevent yourself from experiencing the full extent of keto’s potential benefits. Not only do you sabotage keto’s promised fat loss, clarity, and focus, but your body’s ability to quash inflammation, too.
Another Approach: Carb Cycling
While random days off of keto can undermine your progress and leave you feeling crummy, you can strategically incorporate some carbs and still reap keto’s benefits.
“For some people, particularly those who are extremely active, carb cycling can be a great way to up your carb intake while still reaping the benefits of a ketogenic diet,” says Cole. How does it work? On days you’ll work out hard, you’ll up your carb intake. Otherwise, you keep it keto.
This approach doesn’t mean you can go willy-nilly on desserts on days you hit the gym, but it can certainly create more flexibility.
How To Try Carb Cycling
To carb-cycle properly, stick to your normal keto diet and around 50 grams of total carbs per day for five or six days a week. Then, on one or two non-consecutive days, up your carb intake to 75 to 155 total grams and get your sweat on, says Cole.
On those higher-carb days, just stick to healthy, whole foods, like sweet potatoes, berries, and carrots.
Ideally, this strategy will allow you to both power a couple of higher-intensity workouts a week and reap the benefits of keto.
However, if you notice any major stalls in your keto results—or aren’t truly going hard in the gym on higher-carb days—consider sticking with a standard keto diet.
“While some people can benefit from carb cycling, it’s not appropriate or needed for everyone,” says Cole. “Each person is unique, so what works for one person may not work for the next.”
How To Get Back Into Ketosis—Fast
Whether you’re coming off a strategic high-carb day or just a random day off keto (hello, birthday cake), you’ll want to transition back into fat-burning mode as quickly as possible.
How long it’ll take you to transition back into true ketosis depends on factors like:
- how many carbs you ate
- your sensitivity to carbs
- your physical activity level
Depending on these factors, it may take you anywhere from one to a few days to fully shift back into fat-burning mode.
“While staying on track with a keto diet is important, if you happen to eat something not-so-keto, show yourself some grace and jump back into it the next day,” says Cole.
To really speed up the process, Cole recommends doing a fast. If you really mean business, fasting for 24 hours after your day off goes a long way in helping your body clear out any blood sugar or stored carbs.
If you want to take a less intense approach, just employ basic intermittent fasting and wait until lunchtime or so to have your first meal.
Or, if you don’t want to fast at all, just get back to your regular keto diet and sit tight.
Remember: “Stressing about your diet can be just as detrimental to your health as the foods you put into your body,” says Cole. So be patient and eat those healthy fats!
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