Intermittent fasting and the keto diet have been the most talked about weight loss strategies of the year. Both have been recognised for their health benefits from fat loss to improved mental clarity.

But should the ketogenic diet and intermittent fasting be combined? And if you do both, will it speed up your weight loss and health goals?

Intermittent Fasting: The basics

Intermittent fasting (IF) simply refers to eating during a set period of time and fasting the remaining hours. There are different forms of intermittent fasting where the eating window is adjusted. The most popular and perhaps the easiest fasting method to execute is the 16/8. This means you have an 8-hour window to eat and you’re fasting for 16 hours.

The theory behind the intermittent fasting eating pattern is that you reduce your calorie intake and as a result, your insulin levels will begin to reduce and your ability to burn fat increases.

Why is reducing our insulin levels beneficial? When we consume food, mostly carbohydrates, we release insulin which alerts the body to store excess energy in the form of glycogen for use when we need it. Some of the glycogen stores will be in the liver, but more of it will become body fat.

To put it simply: the more insulin produced = the greater fat stores and as a result, an expanding our waistlines.

The idea behind fasting meal plans is that when our body has been in a fasted state for a certain period of time, it starts to tap into the fat stores and uses this as fuel.

The advantages of IF dieting may include:

  • Reduced fat mass while maintaining muscle mass
  • Improved metabolic health
  • Reduced insulin resistance
  • Stabilises blood sugar levels
  • Boosted brain function
  • Increased energy levels
  • Easy to maintain long term

Ketogenic diet: The basics

The Ketogenic diet is not a new way of eating but certainly gained popularity around keto dieters, nutritionists and other health professionals over the last year or two.

Rather than focus on reduced calorie intake, the keto diet is based on low-carb and high-fat to put the body into a state of ketosis. This is where the body endogenously produces its own ketones and burns fat for fuel instead of using glucose as the glycogen stores are reduced. The body can become ketogenic after days of fasting or a week or two of low-carb dieting.

You can also induce ketosis exogenously when ketones are supplemented. The difference, however, is that your body isn’t producing ketones. Instead, the ketone levels in the blood are raised with supplementation such as medium-chain triglycerides (MCT oils) or ketone salts and esters.

The advantages of a ketogenic diet may include:

  • Reduced body fat
  • Improved appetite control
  • Better diabetes control
  • Improved cholesterol levels
  • Improved metabolic health
  • Improved mental clarity

Combining Keto and Intermittent Fasting

Both these popular dieting methods aim to produce the same goal and that is to encourage the body to use fat-burning for energy and deplete it of glucose.

There is little research that looks into the health benefits of high-fat, low-carb diets combined with intermittent fasting. However, many have found adopting both helpful in escalating their results. This is because fasting can help put the body it into ketosis sooner.

Another one of the benefits of intermittent fasting on a keto diet that is often discussed is the reduced symptoms of the “keto flu” as you enter ketosis faster.

A keto-friendly diet combined with defined feeding windows can also help people get out of their weight loss plateau. This is because you’re reducing your calorie intake and your appetite is well controlled.

While there may be benefits of combining both keto and intermittent fasting, it’s not easy. The macronutrient changes and calorie restriction coupled with the fasting schedule can be challenging. If you have a high workout load, using fat as a fuel source can also take some time to adjust to. On top of this, if it is not planned well, a ketogenic diet can lead to nutritional deficiencies and increase the load on organs such as the liver and kidneys.

Example of a Keto / Intermittent Fasting Hybrid Diet

What might an average day on a keto/fasting diet look like?

7:00 am: water with lemon

10:00 am: black coffee (option with coconut oil) or black tea

1:00 pm: salmon salad with avocado and olive oil dressing

3:30 pm: hard-boiled egg and cucumber

6:00 pm: grilled chicken with steamed green veggies

7:00 pm: herbal tea

The bottom line

There is no one perfect diet that suits everyone with each individual responding differently. Depending on your health status and your current diet, you may be able to achieve your health goals simply by restricting your carb intake or implementing a fasting schedule. Both diets have been shown to be effective on their own and combining them may not be better.

For some, restricting the intake of carbs or fasting alone may be overwhelming and challenging to maintain long-term. If you haven’t tried either diet, it might be worth trying one before you adopt both. Slowly introducing alternate day fasting may also be a helpful way to keep up the healthy habits long-term.

However, if you have reached a weight loss plateau or want to fast track your results, why not give the hybrid diet a go? Our tips for doing it successfully:

  1. Track your food intake to make sure you’re getting the right macronutrient balance and calorie intake.
  2. Measure your ketone levels to see if you’re actually getting into a state of ketosis.
  3. Start with a moderate fasting approach and slowly adjusting the eating window.
  4. Track your results. If you aren’t measuring, you’re guessing.