Sunday, January 4, 2015

Hi David,

Just found your blog today and pretty much read the entire thing in one sitting. 

I'm trying to figure out carbohydrates in my diet. I've been pretty low carb for the past few years, but I'm beginning to feel that perhaps the evidence does point to consuming more carbs for performance, hormonal balance, etc. You seem to feel the same way. I wonder if you have any thoughts on a cyclical ketogenic diet? Such as eating very low carb and staying in ketosis during the week and then "carbing up" on Sunday. This seems to avoid elevated insulin levels for long periods of time while getting all of the benefits of giving your muscles a hit of glucose and helping your thyroid to function better on a somewhat regular basis. 

Do you have any thoughts on resistant starch carbs (seems to be all the rage on the paleo blogosphere currently)?

My other question is in regards to supplements: do you have a recommendation or list of supplements that you take? Also, Vitamin D3 - I try to avoid sun and wear sunscreen every day for anti-aging purposes and take vitamin D. It seems like you do not think this is a good idea and that it would be preferable to get sun daily? If so, how long do you think would be best? Also, antioxidants--do you supplement these (like taking resveratol and such)?

Erm, final question! Fasting and autophagy. Do you think IFing with BPC gives us enough time to get daily autophagy going? Would it be beneficial to not have the BPC to better induce autophagy? I've started doing a weekly 24 hour water fast for this reason, but maybe it's not necessary.

Ok, thanks if you've actually read through this long message! I think your take on nutrition is on the nose and clearly your in super awesome and healthy shape. Kudos!



Thanks for your excellent questions. Clearly you're very well read in the Paleo realm. I'm going to address your questions one by one.

DISCLAIMER: I am not a doctor and this is not medical advice but I'm happy to share my thoughts with you. 

1. Carbohydrates

Let me start by reiterating that I believe the chronic excessive consumption of refined carbohydrates such as flour, sugar and corn syrup is at the root of much modern metabolic disease such as obesity, diabetes and heart disease. 

I don't think that whole food sources of carbohydrate are necessarily "bad" for healthy people and there are many instances of very healthy populations with high longevity who have a carbohydrate-heavy diet from say, rice, corn or roots and tubers. 

Chris Masterjohn did some very interesting work on the prevalence of the amylase gene mutation in humans - an enzyme that helps break down starch. This suggests that we are certainly adapted to digesting rich sources of glucose - more so than other primates - and that increased copies of this gene seem to have an evolutionary benefit. 

And while there are certainly instances of some populations like the Inuit who would have been in ketosis for most of the year, I don’t think that being in a constant and perpetual state of ketosis is desirable or optimal - particularly for fertility and peak human performance. 

Having said that I think we should be fully fat adapted and be in ketosis periodically. The more fat adapted you become the easier it is to switch in and out of ketosis. Intermittent fasting and avoiding carbs and protein in the morning and eating more dietary fat and less carbs are excellent ways to become more fat adapted. If you aren't hungry between meals, don't crave carbs and don't wake up ravenous then that's a good sign you are fat adapted. 

If you aren't doing a lot of high intensity training, aren't looking to get pregnant and/or don't tolerate carbs well then I think a cyclic ketogenic diet could be an appropriate lifestyle for you, so long as you are doing a proper carb re-feed at least once or twice a week. 

Personally, my sweet spot for carbs is about 100-150g a day most days of the week with maybe one or two lower carb days and one or two higher carb days. 

As with most things I think it is important to mix it up. I don't really like the idea of setting a strict schedule for low carb days and high carb days but rather listening to your body and also your circumstances. If you happen to go to a Thai restaurant on a low carb day you want the flexibility to be able to eat some rice if you want, right? 

I know for me that going low carb for months on end screwed me up. Probably because I was doing CrossFit a lot and often having late nights. I started getting lethargic, grumpy and not sleeping well. 

Carbohydrate tolerance varies hugely among the population though. It is a very personal thing and can easily change over your lifetime depending on factors such as stress, sleep, activity levels, season, latitude, etc. 

Some people may eat 150g of carbs a day and develop type II diabetes because they just can't tolerate that amount of glucose over time. Other people could eat 300g a day and have perfect blood sugar control and low levels of inflammation. 

The only real way to tell is to get a glucometer and measure your fasting and post prandial blood glucose over a period of time and see how different amounts of carbohydrates from different sources affect you. I found that my blood sugar rarely goes above 110 even after eating white rice and ice cream, as long as I consume a fair amount of fat and fibre with the meal. So for me I think I can tolerate carbs fairly well. 

You need to self-experiment. Even without a glucometer you should be able to tell if you feel better introducing some more carbs into your diet. 

By the way I am not recommending you go crazy with white rice and ice cream! They certainly shouldn't be staples. 

2. Resistant Starch (RS)

This has definitely been a hot topic in the Paleo-sphere in the last 12 months. For those unfamiliar with resistant starch it is a type of starch that cannot be fully broken down by human digestion so it passes through into the large intestine to be digested by our gut microbes. 

There are four different types of resistant starch, three of these from whole food sources such as unripe bananas or cooked and cooled potatoes and rice. However, it is fairly difficult to get a substantial dose from real foods so typically a refined version of RS such as potato starch or plantain flour is used as a supplement. 

Even though the mechanism isn’t fully understood the anecdotal evidence is that RS improves glucose tolerance (stabilizes blood sugar), can lead to fat loss and other health benefits via an improvement in the state of your gut microbiome (2).

I've looked into it and experimented a bit with potato starch. I didn't notice any benefit and definitely had some issues with gas. Maybe I didn't stick to it long enough.

Even though it is one of the hottest topics in health at the moment our understanding of the gut microbiome remains in its infancy. 

RS has a lot of potential and seems to be helping a lot of people improve their health but it I see it as a very blunt, crude instrument. If RS feeds the good bacteria in our gut, doesn’t it also feed the bad bacteria? Couldn’t RS worsen symptoms for some people whose gut flora is out of whack - like those with Small Intestinal Bacterial Overgrowth? 

It is certainly an interesting area but my gut instinct (see what I did there?) is that it doesn't make sense to eat a refined food such as potato starch in order to get some short-cut benefit. It just doesn't gel well with me and I remain cautious while the evidence for it remains anecdotal at this stage. Many other Paleo professionals such as Dr Tery Wahls feel the same way - that we should focus on pro and probiotics from whole food sources. 

I don't see much harm in trying RS for yourself though, especially if you focus on the real food sources rather than the potato starch. 

3. Vitamin D3 and sun exposure

There is some research out there that sunscreen can be mildly toxic and you may be better off not using it and instead limiting sun exposure to build up a natural tolerance to the sun. But I am an Aussie and where I'm from going out in the summer sun without sunscreen is akin to stirring boiling bone broth with your bare hands - you're gonna get burnt. 

So I think wearing sunscreen on your face to prevent aging is probably a good idea, but I certainly wouldn't be afraid to get some smart sun exposure on your body where possible. You can check the UV on a weather app. Levels of 2-4 are a good time to get some sun without risk of getting burnt. When UV is 4-5 or higher you probably don't want to spend more than 20 minutes without sunscreen. 

In summer you may want to avoid the highest UV times of the day but in winter - assuming you’re from North America or Europe - you probably don't have to worry about sunscreen. I don't wear sunscreen most of the year in New York except for summer. 

In the midday summer sun 30 minutes of sun exposure will produce 10-20,000 IU of vitamin D in someone with pale skin (4). Someone with darker skin will produce less than that. 

Unless you are living in the tropics, and especially if you are darker skinned and living in North America or Europe then Vitamin D3 supplementation is probably a good idea. My vitamin D levels are quite low, which is very surprising considering how much time I spend in the sun. 

5,000 - 8,000 IU of supplemental vitamin D3 can be taken daily pretty safely until you get your Vitamin D levels to at least 35-50ng/mL. Make sure it's D3 and not D2 you are taking. 

4. Supplements

I don’t think it is wise to rely on supplements. Real food sources always trump supplements. The problem is that the supplement industry is a massive and hugely profitable business which is also grossly unregulated. This means there are a lot of snakes out there making false claims and producing very poor quality products. 

Many supplements don’t have solid science behind their proposed benefits and some even may be harmful. 

Having said that, I do take some supplements. In the US you can get some fairly decent supplements at low cost through Amazon. Because it is relatively cheap I am willing to spend a few dollars a month to take certain supplements even though I realize they may not offer a huge benefit. For example I take 10,000mg Biotin for my skin and hair, Milk Thistle for liver function and  Activated Charcoal for when I drink some beers or nasty food. 

The supplements that I do think have value and that I take consistently are the following:

DHA and EPA (Fish oil)

I don’t always eat as much oily fish as I would like to so I supplement with 1000mg of DHA and 500mg of EPA on days that I don’t eat fish. I like this brand:


Due to soil degradation and our modern food system most people don’t get enough magnesium in their diet. I take about 300mg of Ionic magnesium citrate every night before bed. I use Natural Calm. I find that it noticeably improves my sleep.

Vitamin D3

I haven’t supplemented with Vitamin D3 before but now that I know that I have low Vitamin D levels and it is New York winter I am going to start supplementing 10,000 IU a day until I get my levels up and then I will probably stop supplementing until next winter.

Vitamin C

If I feel a cold coming along I will load up on 3,000 - 6,000mg of Vitamin C per day until I get over it. It is such a cheap supplement that even if it doesn’t do much I think it’s worth the placebo. Sometimes I’ll take 1,000mg a day just for maintenance.

Whey Protein

I have a really high quality unflavored whey protein in the cupboard that is 100% grass-fed whey and I use it in smoothies from time to time. BCAAs have many proven benefits and whey is scientifically backed as the best form of supplemental protein. If you are vegan hemp protein is probably the best substitute. Check out my Low Carb High Fat Paleo Super Smoothie.

You may also want to consider eating some seaweed for iodine and oysters for copper and zinc when possible. 

I do not take antioxidant supplements. I think antioxidants should come from food only. From what I’ve heard resveratrol is a waste of money. See the Kresser article below for his supplement recommendations.

5. Fasting and autophagy 

Autophagy, literally ‘self-eating’ is a cell process whereby excess junk and nasties are destroyed and cleared out. It’s like a spring clean of your cells or emptying the trash folder on your computer. It is a very important process for a variety of metabolic pathways and longevity. 

From what I understand autophagy is stimulated by fasting among other things such as sleep, sun exposure, exercise and possibly caffeine. I’ve heard from various sources that protein and carbohydrate consumption can inhibit autophagy but that fat doesn’t. Dave Asprey (the bulletproof coffee guy) says that BPC does not interfere with autophagy and may even boost it. I couldn’t find any science to back this up though. 

Either way I think fasting both with or without bulletproof coffee should still see some benefit from autophagy. 

I find intermittent fasting with bulletproof coffee to be far easier, more sustainable and better from a performance perspective. But, since my mantra is to mix things up I don’t have Bulletproof coffee every time I fast and I certainly don’t have Bulletproof coffee every day. 

I probably intermittent fast five days a week and may have bulletproof coffee on two or three of those days. On the other fast days I just have black coffee or coffee with a splash of heavy cream then workout and break my fast around 2-4pm. On days that I am hungry in the morning I eat breakfast. 

Doing a 24 hour water fast once a week is pretty hardcore. If it makes you happy do it but it’s probably not necessary. Brad Pilon from ‘Eat Stop Eat’ says there isn’t much reason to fast for more than 24 hours. Personally I find any longer than 18-20 hours and I’m fighting myself. 

Remember that the ultimate goal is to find a sustainable, healthy lifestyle that is easier to follow than not to follow. The goal is not perfection but gradual improvement. 

References and further reading:


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