Last Updated on April 12, 2024 by Fasting Planet
The keto diet has taken the world by storm, and not necessarily because it’s another fad, but rather, since people tend to see results. Both the keto diet and fasting have a lot in common, cutting out foods especially. You may have some questions about ketosis as it relates to fasting. For example, can being on a fast help you enter ketosis sooner?
Indeed, intermittent fasts of 24 hours or fewer should allow you to enter a state of ketosis more quickly than going without. Studies also indicate that fasting when on a keto diet can accelerate weight loss.
If you have yet more burning questions about ketosis and fasting, then this is the article for you. Ahead, we’ll discuss ketosis in depth, explain how it’s different than fasting, and dive deeper into the data on how fasting speeds up ketosis.
Let’s begin!
What Is Ketosis?
We’ve discussed ketosis extensively on this blog, but if this is your first time here, we’ll recap all that useful information for you now.
The keto diet activates a process known as ketosis. When your body enters ketosis, it’s due to very specific conditions being met. You’ve stopped providing your body the carbohydrates it uses as an energy source, eating no more than 50 grams of carbs a day. For comparison’s sake, 50 grams is about 0.1102 pounds, so it’s not a lot.
Since your body must have energy to survive, it needs to seek an alternate energy source. Partially, the body will burn fat during ketosis. It also begins torching what are known as ketones, or ketone bodies.
As a type of water-soluble molecule, ketone bodies are produced from fatty acids. Besides eating a low-carb diet, your body can also produce more ketone bodies if you have undiagnosed type 1 diabetes mellitus, alcoholism, you over-exercise for long periods, you’re starving (not necessarily through fasting), or you’re significantly cutting calories but not exclusively carbs.
The ketone bodies you produce will pass through your blood-brain barrier, giving your brain a source of energy when glucose or sugar is in low supply. According to a 2009 report in the journal Advances in Experimental Medicine and Biology, making ketone bodies could even stop your brain from using glucose as an energy source, switching to ketones instead.
Depending on the length of your keto diet, your brain will rely on ketones as an energy source at varying degrees. If your keto diet lasts three days, then a classic report in the Journal of Cerebral Blood Flow & Metabolism notes that roughly 25 percent of your brain’s energy will come from ketone bodies. Should you continue your keto diet for longer periods, then now it’s about 60 percent of your brain’s energy that’s generated from ketone bodies according to a classic study from the Journal of Clinical Investigation.
Think of ketosis as a type of metabolic state, and a good one at that. Ketosis is also totally natural, which is definitely a big part of why the keto diet has caught on with so many people.
How Is Ketosis Different Than Fasting?
Okay, so that’s how ketosis works, but what about intermittent fasting? Are ketosis and fasting different?
Absolutely.
When you go on an intermittent fast, you’re typically not seeking only to restrict carbs, but all calories. This is sometimes the case with a keto diet, but the focus is certainly more on limiting carbs so you can enter ketosis.
The foods you eat, carbs or no carbs, contain differing amounts of glucose. This is a sugar supply the body uses for energy after converting it to glycogen. As a glucose multibranched polysaccharide, the process of glycogenesis converts glucose to glycogen for us humans as well as bacteria, fungi, and animals.
Every time you eat, you provide more glucose that becomes glycogen, keeping your energy levels up. Yet what happens if you suddenly stop eating altogether or limit your calorie consumption to something like 500 calories a day?
Your body doesn’t use every last bit of glucose you supply it when you’re eating normally. The leftover glucose gets stored in the liver. There, it stays until it’s needed. Thus, when you first begin fasting, your body will have plenty of leftover glycogen it can use to keep you feeling energized.
As your body burns through that supply of sugar though, like during ketosis, it needs an energy source. Rather than use ketone bodies though, instead, your system begins mostly burning fat. Sometimes, muscle proteins get burned as well, but this is typically during longer intermittent fasts.
What Are the Benefits of Ketosis?
If you’re planning your first keto diet, you may wonder how you’ll go that long with so few carbs. While a diet of this nature can be difficult, as can fasting, the results are worth it. Here are the benefits you can reap from keto.
Could Treat Epilepsy
Ketone bodies as an energy source for the brain have been proven effective for epileptic patients, especially children. So says a 2008 report from Nutrition in Clinical Practice. That report mentions that when children ate a keto diet, up to 16 percent of them had no more seizures. Another 50 percent had fewer seizures.
Since the keto diet has had such beneficial effects on epilepsy, researchers are looking into how this low-carb way of eating could help those with Parkinson’s and Alzheimer’s.
Can Reduce Metabolic Syndrome Risk Factors
Metabolic syndrome is a group of disorders that could contribute to an early death. The group includes decreased good cholesterol, elevated triglycerides, higher fasting blood sugar, boosted blood pressure, and obesity in the abdominal area.
Yet a 2003 study from the journal Metabolic Syndrome and Related Disorders noted how cutting carbs can reduce metabolic syndrome.
Boosts Good Cholesterol
Besides controlling bad low-density lipoprotein or LDL cholesterol, a low-carb keto diet can also elevate your high-density lipoprotein or HDL cholesterol. When you increase HDL cholesterol while lowering LDL cholesterol, you could have big impacts on your health.
For instance, you could reduce heart disease risk, says Circulation in a classic report.
More Abdominal Cavity Fat Loss
We noted before that excess abdominal fat is one symptom of metabolic syndrome. Worse than that, when visceral fat builds up around your abdominal cavity, it can boost your resistance to insulin as well as your rate of inflammation. You also increase your risk of developing type 2 diabetes and heart disease.
In 2008, Nutrition & Metabolism (London) published data that found that low-carb diets can help those with abdominal cavity fat especially, lessening this fat to reduce the above health risk factors.
Less Ravenous Appetite
If you always feel hungry, cutting carbs may sound like the last thing you want to do. Yet once you start on a keto diet, your appetite can decrease, according to a 2007 report from Obesity (Silver Spring).
Weight Loss
We saved one of the top benefits of a keto diet for last. Since you’re reducing your carb intake so completely through a keto diet, most people tend to lose weight relatively quickly. You might even find that, compared to a low-fat diet, the weight comes off faster.
This is due to losing both the water weight and body fat through a keto diet. That said, after roughly six months, the weight loss comparisons between a low-fat and a low-carb diet become a lot more similar per results from a 2003 trial published in the New England Journal of Medicine.
Does Fasting Allow You to Enter Ketosis Faster?
You’re certainly interested in ketosis, as the keto diet seems like it can be largely advantageous for your health. How long will it take you to enter ketosis if you’re adhering to a low-carb diet?
It can be a while, anywhere from two to seven days depending on what you’re eating. A week can be a long time to go without carbs, but fortunately, you can accelerate the amount of time it takes to enter a ketogenic state.
Here are some methods you can use:
- Consume coconut oil: In a 2015 report published in the British Journal of Nutrition, when a group of participants with Alzheimer’s went on a keto diet and ate coconut oil, their ketone body production went up. This is because of the medium-chain triglycerides within coconut oil, a type of fat that goes right to the liver to become ketones.
- Eat more healthy fats: Besides coconut oil, your keto diet should also center around healthy fats such as flaxseed oil, avocados (or even avocado oil), and olive oil. Just make sure you watch your quantities, as some of these oils can be quite high in calories.
- Cut carbs even further: We wouldn’t recommend this for first-time keto dieters, but if you can eventually aim to consume about 20 grams of carbs a day (or even fewer), that’s ideal for ketosis.
- Exercise more: Although you might not feel like exercising much when limiting carbs, it’s important for ketosis. You can burn through your body’s supply of glycogen faster through physical fitness, which puts you into a ketogenic state faster. That said, don’t exercise yourself to the point of over-exhaustion.
What about if you go on an intermittent fast while following the keto diet? Is it possible to speed up the amount of time it takes you to enter ketosis that way?
Yes, it is. Intermittent fasting allows you to consume some food depending on the type of fast you’re on. With alternate-day fasts, you spend 24 hours fasting then the next 24 hours eating, in this case, abiding by the keto diet.
On the 16:8 fast or some variation thereof, you spend 16 hours fasting and another eight hours eating. The 5:2 diet requires you to cut your calories to no more than 600 calories a day twice a week. Then you’d spend the other five days eating more regularly.
You don’t necessarily have to dedicate yourself to a particularly long fast to speed up ketosis. Short-term fasting for a few hours at a time, even between meals, can put you into a state of ketosis faster than eating continuously.
If you find that’s not the case for you, then you can fast for periods of 24 to 48 hours, typically with a doctor’s approval, when on the keto diet.
Some experts also recommend fat fasting, which we’ve written about on the blog before. If you missed that post, here’s a refresher. Fat fasting is a type of diet where you consume few calories, no more than 1,200. Those calories that you do consume are mostly fat, between 80 and 90 percent.
A 2006 report from Nutrition & Metabolism (London) noted that fat fasting on a keto diet in particular can help you lose weight. That applies if you can keep up with the typical duration of a fat fast, which is between two and five days long.
How Do You Know When You’re in Ketosis When on a Fast?
Through the information in this article, you’ve decided that you’d like to fast to speed up the amount of time it takes for you to enter ketosis. Perhaps you’re on a standard intermittent fast or maybe you even tried fat fasting.
Short of stepping on the scale every day to see if the weight has come off, how do you know if you’re in ketosis? You don’t necessarily have to guess, as there are several ways to gauge the level of ketone bodies in your system at any time one.
Let’s discuss these methods now.
Test for Ketones
You can test for ketones in one of three ways: by testing your urine, your breath, or your blood. Urine tests look for a specific type of ketone known as acetoacetate. The test is a strip that you urinate on or dip into a cup of your urine that you collected.
Depending on the type of urine test you buy, you may have to wait several seconds to upwards of a minute or two for your results.
You can also determine if you’re in ketosis by testing your breath. Yes, that’s right, your breath. One of the more popular ketone breath testers, the Ketonix, needs at least 12 hours of charging prior to use, so make sure you prepare accordingly.
To use the Ketonix and related devices, you want to take a very deep breath. Make sure you use your lung power to really generate the strongest breath you can. It’s also recommended that you haven’t consumed any alcohol and that if you did, that you wait until it’s entirely out of your system before testing.
The Ketonix and many related keto breath testers tend to have an accompanying smartphone app you can use to see your results and determine your keto level changes from one day to another.
Finally, you can test for ketone bodies in the blood by using a blood ketone meter. This tells you how much β-hydroxybutyrate is in your blood. You stick your finger with the meter to produce a blood droplet, then you test that droplet. You also need a strip for testing.
Ketone tests for the urine, breath, and blood are convenient in that you can do them at home, often when the mood strikes you. However, the long charging times of some devices as well as the expense of others might not make this an option for everyone. Also, sometimes the accuracy of at-home testing is called into question. If you do want to test your ketone bodies at home, make sure you do your research into accurate testing measures.
Gauge Your Concentration and Focus
Do you have a headache? Are you finding it tough to concentrate? Believe it or not, these are signs that ketosis is working, at least in the early stretch. Then later, if you find yourself able to focus easily and concentrate better, this too is because of ketosis.
Do a Quick Breath Test
If you don’t have a ketone breath meter, that’s okay. You don’t necessarily need one. Just cup your hand in front of your mouth and blow out. Does your breath kind of reek even though you just brushed your teeth? You’re probably in ketosis.
Some keto dieters report their breath takes on a fruity and sweet aroma while others say their breath tastes more like urine when in ketosis. This may sound gross, but it’s actually a good sign, so keep it up!
Consider Your Thirst
How thirsty are you? If your thirst seems unquenchable lately, it could be because you’ve entered a state of ketosis. When in ketosis, since you lose water, it’s normal to feel thirstier than you typically do.
That said, you must make sure you hydrate yourself, especially when fasting on keto. If you’re in a keto diet for long enough or you fast and boost your count of ketone bodies, you could develop electrolyte imbalances and even become dehydrated. This can be deadly in some instances.
Conclusion
Ketosis is a low-carb state in which your body uses ketones for energy as well as fat. Through fasting, and especially fat fasting, you can speed up the time it takes to enter ketosis. Good luck on your keto diet!