Weight loss power combo: Intermittent fasting and keto diet

Two trends in the diet world are making waves – keto diet and intermittent fasting.

But some are even taking it up a notch and combining the two.

So the big question is  do intermittent fasting and keto diet make a perfect weight loss combination?

This article finds out.


What is intermittent fasting?

Intermittent fasting – or IF – is a kind of diet that focuses on when you’re eating and not eating. Timing is key, as your food intake is divided into three square meals a day. As Healthline puts it: [1]

Intermittent fasting is an eating pattern where you cycle between periods of eating and fasting. It does not say anything about which foods to eat, but rather when you should eat them.

There are different variations for IF, and according to Healthline, some of the common ones are: [2]

  • The 16/8 Method – fast for 16 hours straight and eat within an 8-hour window. Most people achieve this by skipping dinner and breakfast the next day, focusing their food intake on brunch and 2-3 smaller meals within 8 hours. This method is often seen as the most “natural”.
  • The 5:2 Diet – eat normally for 5 days and fast for 2 days in a week. The fasting part doesn’t necessarily have to be zero food intake. This diet requires limiting calorie intake to 500-600 on two days.
  • Eat-Stop-Eat – fast for 24 hours straight, once or twice a week, while eating normally the rest of the time. Most people do this by stopping food intake from breakfast to breakfast (the next day), lunch to lunch, or dinner to dinner. This seems to be the most challenging for many because – hello – fasting for 24 hours nonstop!
  • Alternate-day fasting – fast every other day. Beginners could start with limiting calorie intake to 500 on fasting days. Those who want to go full steam would not eat anything at all every other day. Intense!
  • The Warrior Diet – fast during the day and heavy dinner every night. This is one of the more common ones, where people “eat light” with fruits and veggies, and feast with one massive meal within a 4-hour window at night.
  • Spontaneous meal skipping – not eating whenever it’s convenient. What this means is that you don’t really have to eat if you’re not hungry. If you can skip 1-2 meals in a day spontaneously, then just go for it. The idea behind this is that diet doesn’t have to be structured; the body is well-equipped to handle long periods of hunger anyway. So why not tap into that? This seems to be the go-to diet of busy, on-the-go people!


What is keto diet?

This one’s pretty simple. The ketogenic diet is a low-carb, high-fat diet. It’s said to be effective for weight loss as it significantly lowers down carbs in the diet and involves eating food rich in fat instead. When this happens, the body achieves a metabolic state called ketosis, where it becomes exceptionally efficient in burning fat. This way, the stored fat becomes the primary source of energy instead of glucose. [3, 4]

Because keto diet is rich in fat and low on carbohydrates, it results in lower blood sugar and insulin levels.

Related articles:


Combining intermittent fasting and keto:

5 reasons why it works


1. Easier and faster transition to ketosis

Intermittent fasting aids in reaching ketosis in a faster and more seamless fashion, compared to doing keto diet alone.

And by faster, I mean 24 to 36 hours. [5]

Now here’s the common thing about intermittent fasting and keto diet:

When the body goes through either diet, it sources its energy from fats, instead of the usual carbohydrates and glucose. [6]

This happens because our body’s insulin levels, blood sugar and glycogen stores go down while fasting. Our system then turns to stored fat and starts burning it as fuel source. [7]

There's another major link between the two diets. During intermittent fasting, ketone levels go up, which is exactly what happens with the keto diet.

According to Dominic D’Agostino, PhD, associate professor at the University of South Florida in Tampa and founder: [8]

“The brain will rely less on glucose for energy when in a state of nutritional ketosis. Therefore, the transition into a fasted (ketogenic) state during the day eventually becomes seamless after eating low-carb or ketogenic for a few weeks.”

These processes all together result in weight loss!

2. Say goodbye to *more* fat

A combination of both intermittent fasting and keto diet may lead to burning *more* fat, compared to doing just a single one.

Intermittent fasting has been proven to effectively and carefully get rid of excess and stubborn fats in the body. By virtue of thermogenesis or heat production, IF jacks up metabolism and prompts the body to start tapping into stored fat, even those that have long been in surplus. [9]

Talk about turning the body into a fat-burning machine!

A 2016 study showed that in a group of 34 men who were going through resistance training, those who applied the 16/8 IF method experienced a loss of almost 14% more body fat… compared to those who didn’t. [10]

Another study showed that participants who practiced IF lost more fat mass than those under low-calorie diets. Specifically, they lost an average of 7.3 pounds more fat mass than the latter group. [11]


3. Effective body-building among athletes and gym rats

IF also helps keep your toned abs and biceps during weight loss. This diet preserves muscle mass and even makes energy levels higher. This is a welcome perk among those going through keto diet, looking to enhance their athletic/sports performance and drop their body fat at the same time. [12, 13]


4. Bid goodbye to cravings

Did you know that a stable and low blood sugar level can lead to less cravings, fatigue and mood swings? So when you go on a keto diet, it not only keeps your blood sugar at bay, you can also reap the benefits of not having those pesky cravings. [14] This makes intermittent fasting and weight loss so much easier!


5. No more hunger games

Keto diet also curbs hunger. During this diet, the liver burns fat and turns them into energy called ketones. They then go to the bloodstream to be used by cells as energy and fuel.

Ketones also fend off ghrelin, the hunger hormone. When your ghrelin is high, you feel like you’re starving to death.

But during keto diet, ghrelin levels are low. So even when you’re going through IF, you don’t feel too hungry. Fasting then becomes so much easier, and you become more capable of fasting in longer windows.

IF also suppresses hunger. Studies showed that IF can make you feel full, helping you lose weight more easily. [15]  


Is this power combo for everyone?

We’ve seen how this powerful combination is a perfect complement to each other and can enhance each other’s effectivity. But can everyone do both at the same time?

Not necessarily.

First and foremost, if you’re a beginner in either of the two, you may be better off doing one first.

Jumping straight to both may be a shock to the system, and could be counter-productive in the long run.

It’s better to go on more than a couple of weeks first and see if you’d like to ramp up the results. Consult your dietician or a healthcare professional if your overall wellness will allow for it.

Those who have pre-diabetes or diabetes conditions should be careful about not eating for long periods.

Same with those who have chronic kidney disease, eating disorders (or a history of), going through cancer treatments, pregnant or breastfeeding women.