Should you fast on the carnivore diet? Episode 04

Should you fast on the carnivore diet? Episode 04

In this episode I wanted to discuss more about fasting on the carnivore diet. Is it needed? Or is it harmful? Let's start by talking about intermittent fasting - what is it and why is it useful?

In the last episode I went into a little bit more detail about my carnivore journey but in this episode I wanted to discuss more about fasting on the carnivore diet.

Is it needed? Or is it harmful?

Let's start by talking about intermittent fasting - what is it and why is it useful?


Welcome to the Meat Medic Podcast. I'm your host Dr Suresh Khirwadkar.

I'm a GP a lifestyle physician and I'm a practicing carnivore. I've had great success myself personally and with patients by following a carnivore diet and I want to spread the word about the many benefits of eating meat.

In the last episode I went into a little bit more detail about my carnivore journey but in this episode I wanted to discuss more about fasting on the carnivore diet.

Is it needed? Or is it harmful?

Let's start by talking about intermittent fasting - what is it and why is it useful?

What is intermittent fasting?

So intermittent fasting is basically restricting your eating to a certain time window. It's sometimes called time restricted eating and usually it's done by skipping breakfast and possibly lunch. You also need to skip anything really that will cause your insulin to jump so, you can't just have a milky coffee and then skip breakfast, then you're not really doing fasting. You're actually really just not eating and then you will probably get some issues.

Some people say you can do a Bulletproof Coffee whilst fasting - that's having fat or oil in your coffee - no milk or just eating butter.

I don't do these as they will break a fast most likely, although I'm not 100 sure about that one I don't think it's been studied to my knowledge.

If you really wanted to test it well you could do a fasting insulin and then eat butter and then repeat the fasting insulin test. This will tell you if it's going to break a fast or not. We know fat doesn't really raise insulin at all so butter shouldn't do much but it probably will do a little because butter does still have some protein and a little bit of sugar, although not much, it could be enough to technically break the fast.

Realistically it's probably fine.

Now some people do 16 hour fasts, some do 18, some 20 and so on.

Some like the patient I saw the other day does alternate day fasting. There's really no set pattern that you have to follow you just do what works for you.

Why bother fasting at all?

Why bother with restricting your eating times? Well the real reason we want to fast is to reduce our insulin resistance, primarily our insulin levels and put us into a so-called fasted state. The fasting state refers to the metabolism switching over from glucose and carbs to ketones and fat, possibly protein, though likely only in a starvation setting. This is the opposite of what we call the FED state in which we use glucose as fuel.

Now I disagree with these definitions and I know others out there do as well.

I believe our natural state is the fasting state you just have to look at babies the vast majority of the time they're actually in nutritional ketosis

Look at almost every other animal on the planet maybe even all of them I'm not sure entirely, they mostly use fatty acids as fuel, even for example cows eating grass - they're not really actually eating the carbohydrates they're not actually getting the cellulose directly, they're actually absorbing fatty acids which are produced by bacteria that feed on the cellulose in the grass. So they're actually using fat as fuel not carbs (not the grass).

So what happens when we get into this so-called fasted state? Well our insulin rather is as low as possible and the longer that goes for, the longer the fasting goes for, the lower our insulin resistance will go, which is a good thing.

Our insulin sensitivity also increases which is good as well. The low insulin environment will also trigger autophagy.

Autophagy and Leptin

Autophagy is the body's repair and recycle mechanisms and is essential for proper maintenance of the body, and we want to be having this. In our fasted State we can also unblock the hormone leptin and start to utilize our fat stores. Leptin is primarily produced from our fat cells and it basically tells the brain that you've had enough fat already and it doesn't need to make any more, and you don't need to eat more. So in our fasted state the brain can actually see our fat stores and utilize them.

Insulin will really block both of these mechanisms. Once we can use our fat we have almost endless supply of energy.

So the average human being has around 600 grams of stored carbs glycogen in the liver and muscle, that equates to approximately 2400 calories (as one gram of carbs is about four calories in energy). Now compare that to your fat stores. I couldn't really find any hard data on the average body fat percentage, but given around 70% of American adults are obese the chances are it's going to be pretty high, so yes yes I'd said 70% that is a ridiculously high number I will put a link to the paper that I got this from, but yeah that's a pretty accurate number actually.

Let's just use my approximate body weight and fat percentage around 70 kilograms and roughly 25 percent so that means I have around 17 and a half kilograms of fat. Fat is around 9 calories per gram so that means my fat stores are around 157000 calories as potential energy stored in my fat. Just a little bit more than the 2400 we have stored as carbs.

But if your insulin is high it's pretty much literally locking away your fat stores and you can't actually use them.

Now I couldn't really find any evidence to back this up, but my theory is that this is what the runner's Second Wind really is - it's really your body unlocking your fat stores.

Most people have experienced this at some point - you're pretty exhausted with exercise you're barely able to keep going, but you you kind of keep pushing through and then somehow you get this energy out of nowhere and we call that second wind. Suddenly you can seem to just carry on easily and almost go forever. You may be not exactly as fast as you were but you're pretty close, but seemingly just endless energy.

And my theory here is that your insulin has been forced way down through the exercise and just burning the glucose and now suddenly you can actually unlock your fat stores. I think it's a good theory at least and I'd love to be proven correct or wrong. To be fair if anyone out there knows any data on this look please let me know.

Fasting vs FED

So anyway it sounds like we kind of want to be in this fasted state all the time, surely? Why is it called the fasted state in the first place? Well really this just refers to when we were originally looking at this and we have the FED State versus the fasted state. Now the FED state was basically when people were eating carbohydrates so the insulin was high and we really thought this was actually the normal diet. All the time we all thought this was a normal metabolism so we called that fed and we call the opposite fasting.

So do we want to be in a fasted state all the time? Well I would argue that we should and I know that others argue that as well, but we don't need to fast all the time.

I mean you can't fast all the time. You can't just never eat, you will probably eventually die, which is not good!

Now the longest fast on record I think is around 387 days I believe Angus Barbeiri, a Scottish man. I'll cover that again in another episode but I wouldn't recommend you fast for 387 days.

So we can't fast all the time but we can be in the fasted state the whole time.

So how come?

Fasting mimicking diet

Well we said that it's a fasted state not fasting state. The fasted state is when our insulin is low.

Now one of the best ways to drop your insulin level is to follow a low carb diet like keto or carnivore. Carnivore is an almost zero carb way of eating and will keep you in the fastest state the vast majority of the time.

Now keto should do the same, so the question is do we need to fast as well as doing carnivore diet?

Well sadly there's no real studies that have looked at this specific question at least that I could find, but many people believe you don't need to because your body really is already in the fastest State due to the low insulin levels that you're in, and you are really already getting almost all of the benefits.

Now this is really evidenced I think by studies on the fasting mimicking diet which really was specifically designed to emulate fasting in a long-term, sustainable way and gives very similar results to fasting.

Now what's another word for a fasting mimicking diet? The ketogenic diet!

Carnivore is a form of ketogenic diet and we'll be putting us in the fasted state the vast vast majority of the time, if not pretty much all the time. Given that we're already in the fasted state, whilst it's possible, I think it's unlikely that extra fasting is going to have a significant impact.

Natural fasting?

Now many that do carnivore are really actually naturally fasting anyway because they really don't eat when they're not hungry. Some suggest we should specifically add fasting both intermittent and prolonged therapeutic fasting like maybe five or even seven days. I've even seen some people saying they regularly do 30 day fasts, even I think I saw one person saying they did 42-day fasts every three months I mean that's like fasting 42 days on 42 days off 42 days on I mean it's ridiculous. It's totally excessive and completely not required.

Now I believe anyway there's barely any benefits Beyond seven days other than simply the calorie reduction from not eating, and there are significant risks but if you want to learn more about prolonged fasting I will be doing an episode on this as well so do make sure you subscribe to my podcast.

So I think the real question here is you know do I think forced intermittent fasting is required on the carnivore diet?


Is it helpful?



I personally think if you're eating intuitively you'll likely be occasionally fasting naturally and I don't think forcing intermittent fasting on top is required. If you want to do intermittent fasting, go ahead there's no harm, but I really wouldn't worry about it at all.

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