Intermittent Fasting Vs. Keto


Intermittent Fasting and Keto are two of the most popular diet plans for weight loss, but it can be tough knowing which, if either, are right for you. We break it down, exploring what each entail and the potential pros and cons.

Let’s start with Keto. Keto is a low carb, high fat diet. It involves reducing carbohydrate intake and replacing it with fat, as the reduction in carbs puts your body into the metabolic state of ketosis, where your body doesn’t have enough carbs to burn, so it burns stored fat for energy instead. When in ketosis your body becomes more efficient at burning fat for energy, as your body is producing ketones at an accelerated rate. Once the level of ketones in your body reaches a certain threshold you are considered to be in nutritional ketosis.

There are several variations on the Ketogenic diet. The Standard Ketogenic Diet (SKD) is low carb, moderate protein and high fat, a slight variation on this is the high protein KD. Some opt for the Cyclical Ketogenic Diet, which involves periods of higher carb refeeds, for example, five days of Keto followed by two high carb days. Following on from this is the Targeted Ketogenic Diet which allows you to add carbs around your workouts. If you do decide to try out a Keto diet you can tailor it to suit you, dependent on how much you want to reduce your carb intake. A Keto diet is typically 20 grams of net carbs or fewer per day. However, there are certain groups who require special consideration if contemplating a Ketogenic diet plan. These groups include those who take medication for diabetes (such as insulin) and those with high blood pressure or who are breast feeding.

In terms of the benefits of Keto, you don’t need to count calories if the foods you are eating are on the Keto approved list. It is advised to eat when you’re hungry and to stop eating when you feel satiated. A lower carb diet also increases resting energy expenditure, which means you’ll have a higher metabolic rate. However, Keto is extremely restrictive as it does involve cutting out certain food groups completely. Moreover, we don’t know how safe it is and it is not advised to practice Keto for extended amounts of time.

Now, on to Intermittent Fasting. Intermittent fasting centres around the practice of consuming all your meals within an allotted eating time for various health benefits. This time is commonly split between sixteen hours of fasting and eight hours of eating. This is primarily for those who use Intermittent Fasting as a weight loss tool. However, there are many ways you can split your time, depending on your schedule, some people choose to fast for twelve hours and eat for ten.

The truth of the matter is the longer the fasting period, the more effective the benefits. Using the traditional time split, many aim to stop eating by 8pm, skip breakfast and start eating at noon the next day – that includes waiting to have your morning coffee! It’s a myth that breakfast is the most important meal of the day, one perpetuated by cereal brands in an attempt to sell more product.

During fasting your insulin blood levels drop significantly and your growth hormone levels will rise, which helps to facilitate fat burning. It can take 10 to 12 hours to use up the calories in the liver before a metabolic shift occurs to use stored fat. Hence why many opt for the 16:8 split. Short-term fasting also increases your metabolic rate by 3.6-14% which helps to burn more calories. It has been shown to cause less muscle loss than continuous calorie restriction.

Both Ketogenic Diets and Intermittent Fasting can cause a reduction in blood sugar levels. However, one involves restricting certain foods while the other involves restricting the time in which you eat. Arguably Intermittent Fasting is less restrictive as you are not completely cutting out certain food groups. It’s more of a lifestyle change than a diet change, and you are in control of the timings. Keto can also have an impact on your social life as it can make going out for dinner with friends slightly tricky. Intermittent Fasting could also impact this, although you are able to adjust the timings where necessary. The downside of Intermittent Fasting is that the longer-term studies are lacking.

Neither Intermittent Fasting nor Keto can be determined to be better than the other. Both can be effective, but it’s all dependent on the individual and which best suits your lifestyle. It may be the case that neither of these diets are for you. Ultimately the aim is to make healthy lifestyle choices that are maintainable.

If you enjoyed this then check out our post on the core vitamins every runner needs, for another nutritional read.