The keto diet and intermittent fasting are two of the hottest current health trends.
Many health-conscious people use these methods to drop weight and control certain health conditions.
While both have solid research backing their purported benefits, many people wonder if it’s safe and effective to combine the two.
This article defines intermittent fasting and the keto diet and explains whether combining the two is a good idea.
What Is Intermittent Fasting?
Fasting itself has been around almost as long as humans have been around. Hippocrates and Plato were fans of fasting. And most major religions have rituals that involve the practice. But using fasting to lose weight or for other health benefits is relatively new and has attracted more modern philosophers like Hugh Jackman, Nicole Kidman, and Benedict Cumberbatch. And while there are many ways to go about fasting, most of them fall into one of three methods.
The first: alternate-day fasting, where every other day you eat a small 500-calorie meal. The second: the 5:2 diet, in which you eat normally for five days and then eat a 500-calorie meal on your two fasting days;Third: the time-restricted diet, in which you eat as you normally would; but you cram it into a six or eight-hour window of time.
So why is fasting different than eating less throughout the day?
When we eat, we create more energy than we can use. This excess energy gets stored for later use. And there are two places to store this energy. First, there’s the liver, where the energy
is stored as glycogen. The problem is, there’s not a lot of storage in the liver. So when it’s full, the liver turns the excess into fat, which can be exported all over the body, which has unlimited storage space.
But it takes about ten to twelve hours for the energy stored in the liver to be used up. So when we fast for longer than that, this lowers our level of insulin, the hormone that helps store energy, and this tells the body to begin to use the energy it’s stored as fat. The benefits may go beyond weight loss. When the body switches to using fat stores for energy, it produces compounds called ketones, which have been found to have benefits for our brain health. One theory is that intermittent fasting is beneficial because fasting produces a mild form of stress that activates our cellular immune system to release protective proteins.
So the real question: should we try it?
The answer, like so many things involving Benedict Cumberbatch, is complicated. First of all, most of the studies showing the benefits of intermittent fasting were done on mice. There have been a few studies on humans, however, some of which showed that intermittent fasting can be more effective for weight loss than simple low-calorie diets. Another showed a reduced cardiovascular risk.
So, if you have a mouse, and he or she is having weight problems, sure, give it a try. The problem for the rest of us is that it’s difficult. Although it’s closer to how our ancestors ate, there weren’t a lot of snacks around in the hunter-gatherer times, it’s hard in the age of plenty. And it should not be tried by pregnant women, children, the elderly, those with diabetes and those on medicine. If you’re going to try it, experts advise that you go slow, warning that the first week or two might involve headaches, tiredness, and grouchiness. So for the brave ones, happy not eating!
What Is the Keto Diet?
The ketogenic diet (or keto) is a diet that advocates a very low consumption of carbohydrates thanks to a higher intake of lipids.
The person who follows a ketogenic diet will have to exclude almost completely from his diet foods rich in carbohydrates (less than 50g per day) such as cereal products (bread, pasta, cereals, etc.), starchy foods, legumes, products that contain added sugar (cookies, pastries) as well as fruits and many overly “sweet” vegetables.
The menu will include meat, fish, seafood, eggs, nuts, high-fat plain yogurt, dairy products, vegetable oils, and leafy green vegetables.
The principle of the ketogenic diet is simple: by decreasing the intake of carbohydrates;our body will draw on our fats to find energy.
Our liver will then produce acetone and acetylacetonate which will be transformed into ketone bodies. The fat thus metabolized creates what is called a “nutritional ketosis” state. Fats thus become our main source of energy.
Can you do Keto and intermittent fasting at the same time?
Benefits of Practicing Keto Diet and Intermittent Fasting
If you commit to the ketogenic diet while doing intermittent fasting as well, it could offer the following benefits.
May Smooth Your Path to Ketosis
Intermittent fasting may help your body reach ketosis quicker than the keto diet alone.
That’s because your body, when fasting, maintains its energy balance by shifting its fuel source from carbs to fats — the exact premise of the keto diet (11Trusted Source).
During fasting, insulin levels and glycogen stores decrease, leading your body to naturally start burning fat for fuel (12Trusted Source).
For anyone who struggles to reach ketosis while on a keto diet, adding intermittent fasting may effectively jumpstart your process.
May Lead to More Fat Loss
Combining the diet and the fast may help you burn more fat than the diet alone.
Because intermittent fasting boosts metabolism by promoting thermogenesis, or heat production, your body may start utilizing stubborn fat stores (13Trusted Source).
Several studies reveal that intermittent fasting can powerfully and safely drop excess body fat.
In an eight-week study in 34 resistance-trained men, those who practiced the 16/8 method of intermittent fasting lost nearly 14% more body fat than those following a normal eating pattern (14Trusted Source).
Similarly; a review of 28 studies noted that people who used intermittent fasting lost an average of 7.3 pounds (3.3 kg) more fat mass than those following very low-calorie diets (15Trusted Source).
Plus;intermittent fasting may preserve muscle mass during weight loss and improve energy levels, which may be helpful for keto dieters looking to improve athletic performance and drop body fat (16Trusted Source, 17Trusted Source).
Additionally, studies underscore that intermittent fasting can reduce hunger and promote feelings of fullness; which may aid weight loss (18Trusted Source).
SUMMARYCombining intermittent fasting with a keto diet may help you reach ketosis faster and drop more body fat than a keto diet alone.
Should You Combine Them?
Combining the ketogenic diet with intermittent fasting is likely safe for most people.
However, pregnant or breastfeeding women and those with a history of disordered eating should avoid intermittent fasting.
People with certain health conditions, such as diabetes or heart disease, should consult with a doctor before trying intermittent fasting on the keto diet.
Though some people may find merging the practices helpful, it’s important to note that it may not work for everyone.
Some people may find that fasting on the keto diet is too difficult, or they may experience adverse reactions, such as overeating on non-fasting days, irritability, and fatigue (19Trusted Source).
Keep in mind that intermittent fasting is not necessary to reach ketosis, even though it can be used as a tool to do so quickly.
Simply following a healthy, well-rounded keto diet is enough for anyone looking to improve health by cutting down on carbs.
SUMMARYThough simultaneous intermittent fasting and ketogenic dieting may enhance each other’s effectiveness, it’s unnecessary to combine both. Depending on your health goals, you may choose one over the other.
The Bottom Line
Combining the keto diet with intermittent fasting may help you reach ketosis faster than a keto diet alone. It may also result in greater fat loss.
However, while this method may work wonders for some; it’s not necessary to mix both, and some people should avoid this combination.
You’re welcome to experiment and see whether a combination — or one practice on its own — works best for you. But as with any major lifestyle change, it’s advisable to speak to your healthcare provider first.