You’re eager to burn off some extra pounds. After a few failed fad diets, you want to try a diet that will truly work. You’ve narrowed down your options to keto or intermittent fasting. Between the two diets, which is the more effective option?
Both the keto diet and intermittent fasting will help you reduce your caloric load and burn body fat. Keto is the preferable diet for many people because you can eat when you’re hungry, not during assigned eating windows such as when intermittent fasting.
In this guide, we’ll first explore intermittent fasting and then keto separately, then put them head to head to determine which is the better diet. We’ll even talk about whether it’s safe to combine the two diets, so keep reading!
What Is Intermittent Fasting?
For some people, fasting is something you do for a religious observance or the night before a medical test. Many more people have realized that sometimes the best diet isn’t one that only cuts calories but removes them from the equation entirely.
That’s the basis of fasting, to go periods of time without eating or drinking calories. Since people can’t survive without food or drink for too many days, you can only fast consecutively for a while.
An intermittent fasting diet can last much longer because you have eating and drinking windows.
We’ve discussed the types of intermittent fasts on the blog before, and they run the gamut. With some types of intermittent fasts, you forego food and caloric beverages for 24-hour increments, then you eat for the next 24 hours.
This is called alternate-day fasting.
Other types of intermittent fasts allow you to eat for eight hours and then fast for 16 hours, which is the 16/8 method. More generous fasts than that require you to eat no more than 500 calories twice a week. Then the other five days, you could eat normally. This is called the 5:2 diet.
One of the most extreme intermittent fasts of all is the one-meal-a-day or OMAD diet. You get one hour to eat whatever you want. Then you spend the other 23 hours fasting.
Intermittent fasting works like this. You eat fewer calories than you burn, and you lose weight. Some people who try intermittent fasting shed huge amounts of weight and others less so.
Plenty of factors dictate your weight loss potential when intermittent fasting. The type of fast you do, what you eat, whether you exercise, and your age and metabolism are some such factors.
As a whole, intermittent fasting can be a great diet for people who haven’t had success dieting in other ways. Some types of intermittent fasting barely even feel like a diet.
Take the 16/8 method, which is modifiable as long as it encompasses all 24 hours in a day. Let’s say you start with an easier version of the 16/8 method like the 14/10 diet. This means you fast for 14 hours, and you can eat for 10 hours.
If you’re getting eight hours of sleep per night as you should, that’s already six hours of your fasting window gone. Yes, you’re technically intermittent fasting as you sleep since you’re not eating. Then you only have to go eight more hours without food. If your day is busy enough, that’s not too hard.
What Is the Keto Diet?
Then there’s the keto diet, which is short for the ketogenic diet. There are no periods of foregoing food on the keto diet. Instead, you modify the foods you consume.
On the keto diet, you eat a small amount of carbs, a moderate amount of protein, and a large amount of fat. Depending on which version of the keto diet you follow, your allowed dietary percentages vary.
For example, the standard keto diet requires that 10 percent of your diet is carbs, 20 percent is protein, and 70 percent is fat. Your carb load would be between 20 and 50 grams per day.
The cyclical ketogenic diet increases your carb load on refeed days. For instance, you might spend five days per week on the standard keto diet, then have two carb refeed days in which you consume more than 50 grams of carbs.
A high-protein keto diet ups your protein load to 35 percent. Your diet should be only five percent carbs and 60 percent fat.
Why balance the amount of carbs, fat, and protein you ingest on keto? The point is to encourage your body to burn fat. This is something you can do on the intermittent fasting diet too, so let’s explain it now.
When you consume food, it’s converted into glucose or sugar. The liver transforms the glucose into usable energy in a process called glycogenesis. The energy is glycogen. It’s glycogen that fuels our day-to-day activities, from finishing up a big work project to exercising at the gym.
Some food sources contain more glucose than others, and carbs are at the top of that list. By cutting carbs, your body runs out of glucose and thus glycogen. Your liver usually has some backup glucose stored for just such an occasion.
It releases that glucose and your body uses it for energy. But what happens when there’s no leftover glucose? Your body has to keep you energized somehow, so it begins burning fat instead.
This is how you can lose weight when intermittent fasting or on keto. Ketone bodies are produced when you start running out of glucose. When your ketone bodies reach a certain point, you’re in a fat-burning state known as ketosis.
Intermittent Fasting vs. Keto – Which Is Better?
Now that you understand the basics of both intermittent fasting and keto, it’s time to determine which is better.
As we discussed in the intro and the last section, both intermittent fasting and keto can help you achieve your weight loss goals. That said, we think that keto is the easier diet to start and maintain for these reasons.
Skipping Food for Long Periods Isn’t Easy
According to an article from Harvard T.H. Chan School of Public Health, the failure rate for intermittent fasting is up to 65 percent. Yes, that means that over half of people who try intermittent fasting might quit.
It’s not necessarily their fault. It’s just that people are meant to eat. There’s even a belief among some experts that we’re hard-wired to overeat, such as this RAND research brief suggests.
Sure, on the days when you’re busy, it might not be such a big deal to go 12 hours without food, but what about on a lazy Sunday afternoon? All you can think about is your rumbling stomach. You try to drink water, but it’s not enough to quell your hunger.
The keto diet doesn’t put you in that sort of situation. You can eat three meals a day and even snacks and dessert. If your meals are keto-friendly, then you’ll stay in ketogenesis, which should help the pounds come off.
Of course, the fewer calories you eat, the better, just as with any diet.
Some Intermittent Fasts Are TOO Generous
Speaking of calories, we must next discuss the eating window afforded to you when intermittent fasting. There is no limit on what you can ingest in that eating window.
Sure, dietitians and nutritionists recommend you select dense, nutritionally balanced meals to provide you energy for the next period of fasting. Let’s be real, though. If you just fasted for 16 hours and you’ve been salivating at the thought of a big, juicy cheeseburger, you’re going to eat a cheeseburger.
The propensity for eating unhealthy meals is especially apparent in the OMAD diet. You get one hour to eat, which can cause some people to try to cram a whole day’s worth of calories in 60 minutes. We’re talking an entire pizza, chicken wings, breakfast, and dessert.
If you eat 3,000 calories in one hour or in six hours, it’s still 3,000 calories. Even if you don’t eat for the remaining 23 hours, you’re not going to lose weight. If anything, you might gain some pounds.
Not everyone goes hog wild like that when on the OMAD diet, but it is a risk. The empty calories tend to make you hungrier later, which can then enforce the pattern of overeating.
We won’t say that keto is all about clean eating–there is the dirty keto diet, after all–but when you’re not starving, you can make more sound eating decisions.
Plus, there are healthy keto versions of about every meal under the sun, from keto pizza to sweets. If you eat what you want (within reason, of course), the craving disappears. Now you’re not at risk of derailing your diet.
You’re Not Necessarily Limiting Carb Consumption on an Intermittent Fast
It’s not just calories that are hard to restrict when you have a limited eating window such as when intermittent fasting. It’s carbs as well.
No type of intermittent fasting diet is concerned with how few carbs you consume, only how few calories. It’s the periods of not eating that allow you to burn fat, not the reduced carb load.
You might still lose weight on the intermittent fasting diet, but it’s not the healthiest choice. A high-carb diet could put you at a higher risk of sleep apnea, osteoarthritis, liver disease, high blood pressure, high cholesterol, gallbladder disease, and cancer.
By following a ketogenic diet, you can cut both carbs and calories for a healthier, trimmer you.
Exercising While Fasting Is Hard
When you haven’t eaten for 23 hours, the last thing you’re going to want to do is exercise. Since your body needs fuel to keep you going, exercising on an empty stomach can be risky. You could feel weak and faint, and your strength and performance will suffer.
Your risk of injury is a lot higher than when you exercise with a full stomach.
The keto diet ensures that you’re fueling your body with healthy fats and protein so whether you want to go for a run or lift weights, you don’t have to worry about feeling woozy!
Can You Combine Intermittent Fasting and Keto?
If you just can’t decide between intermittent fasting and keto, no one says you have to. You can always combine the two diets. As we wrote about here, you can lose about four pounds a week on intermittent fasting and keto.
Although that doesn’t sound like a lot, you could lose upwards of 72 pounds in a year by maintaining the diet!
Keto and intermittent fasting both require you to reduce calories to burn fat instead of glucose from food. The intermittent fasting diet though is difficult to maintain, as the hunger you feel can make your day-to-day life tough.
On the keto diet, you can eat nutritious, balanced, low-carb meals when you’re hungry so you have the energy and focus to enjoy your life, not slog through it!