Self-experiment: 7 day carb test

Guinea pig time! This n=1 experiment comes from Wired to Eat, Robb Wolf latest (and greatest IMO) piece of work. Robb Wolf is one of the most respected voices in the paleo/ancestral scene not only because he was one of the early adopters, but because he gets science, both at an academic level (he is a biochemist) and at a philosophic level (he is not afraid of changing his views when new evidence is available, which is the case with this book).

I encourage you to listen to a few of the many podcasts Robb has been interviewed in, so that you get an idea of what his book’s message is. I will just offer a very brief summary before presenting my results. After publishing his first book, The Paleo Solution, Robb realised that the paleo prescription as a blanket recommendation was not as effective as a more personalised approach. Studies like Personalized Nutrition by Prediction of Glycemic Responses, which showed wild variations in the blood sugar of people after eating the same foods. That’s why Robb recommends a 7 day carb test (following by a 30 day reset if you’re not currently eating a basic unprocessed paleo-style diet) to find out your individual tolerance to carbohydrate-containing foods.

You may be familiar with this test if you have ever done an oral glucose tolerance test (OGTT) or have served as a volunteer to find out the glycemic index of a particular food. Glycemic index is a measure of the degree that food rises blood sugar. The idea is that you eat a portion of the food (when I did it in uni was either white sandwich bread or sweetened yoghurt) that contains 50g of effective carbohydrate (i.e. total carbohydrate minus fibre) first thing in the morning (this will be your breakfast) and measure your blood glucose 2 hours later (aka 2 hour post-prandial blood glucose). Ideally, your body will release the insulin required to get the sugar out of the blood and into the cells, so that your blood sugar level will be on its way to normal (anywhere between 5.0 and 6.4 mmol/L are Robb’s recommendations based on clinical experience). If your blood sugar is higher than that, Robb recommends halving the portion so that it gives you 25g effective carbohydrate and testing another day, so that you find out the amount of that particular food you can deal with. If your blood sugar is again too high, you’d better stay away from that particular food.

So what do you need for the test?

  1. I recommend buying the book and reading it beforehand so that you get all the background and detailed instructions/handholding if required.
  2. Clean up your diet if you haven’t done so yet.
  3. Get a blood glucose monitor (aka glucometer). I went to Accu Chek’s website and found out they offer a monitor for free! You need to fill out your details so that they can suggest a model to suit your needs and send you the monitor. The catch is that you need to buy the lancets and test strips at a chemist (they are cheaper if you have a diabetes card).



  4. Get a kitchen scale so that you can get accurate portion sizes.
  5. Decide which foods you want to test. These have to be foods that are mainly carbohydrate, such as rice, potatoes, oats, corn, beans, bread, pasta, fruit, etc. Most importantly, these foods should be relevant to you, there’s no point in testing rice if you never eat it nor want to, or testing regular bread if you are gluten intolerant.
  6. Use the book to find out portion sizes of your test foods or calculate them using nutrition panels/databases. If you need help with this, leave a comment on this post.
  7. Start testing! For each day write down as a minimum: the food you tested, the portion size and your blood glucose after 2 hours. Robb included a more comprehensive workbook as a bonus when preordering his book, but if you don’t have it, you want to pay attention to how you feel after eating that particular food. This can give you an indication of how your body is dealing with it.

I decided to test my fasting (i.e. before eating) blood glucose as well as the 2 hour post-prandial just because I wanted to measure the difference between both and also pick up on any confounders (i.e. did I start the day with elevated blood sugar and it wasn’t entirely the foods fault?). You don’t have to do this. I have also included photos of all the foods I tested so that you can see what the portion sizes looked like. Turns out that eating a big whack of carbs with no seasoning or fat is not as enjoyable. I felt bloated and gassy with all the foods in varying degrees, but didn’t feel particularly horrible after any of them.

Day Food Weight (g) Fasting BGL (mmol/L) 2-hr BGL (mmol/L) Delta (mmol/L)
1 Potato, sebago, boiled 457 5.1 7.3 2.2
2 Sweet potato, orange, baked, peeled 290 4.8 5.4 0.6
3 Rice, basmati, boiled 216 5.7 6.2 0.5
4 Steel cut oats 90* 5.3 5.8 0.5
5 Rolled oats 87* 4.7 5.5 0.8
6 Gluten-free bread 139 4.7 4.7 0.0
7 Potato, sebago, boiled 229 5.1 5.4 0.3
8** Hot chips 177 4.9 6.2 1.3
9** Potato with avocado oil mayonnaise 396 5.0 6.1 1.1

* For the oats I measured the dry (uncooked) weight because I calculated the amount using the nutrition panel.

** Days 8 and 9 were bonus days. My friend Timmy was curious about the hot chips, so I did the test. They didn’t spike my blood sugar as bad as the plain potatoes because fat lowers the glycemic index of foods. Then my friend Sandy wondered how the hot chips would compare to cooked and cooled potatoes served with homemade avocado oil mayonnaise. Despite this option being a lot healthier and tastier, there was no real difference in glycemic response. Having said that, it’s important to note that the blood sugar rise is not the only thing to look at. Are Maccas hot chips healthier than boiled potatoes? Hell no!, for a multitude of reasons. Let’s not get blinded by a single number and always look at the full picture.

So what did I learn from my tests? One, that I had a pretty decent response to most of the foods I tested except for potatoes. Alvaro had a pretty good response to them (5.9 mmol/L) and a crappy response to rice (7.4 mmol/L), which was just fine for me. Interesting results if you consider that we should have more or less the same response given that we’re both Peruvian… BUT! I’m 1/2 Japanese and he’s only 1/8 Chinese. So it looks like my carbohydrate metabolism genes are more Asian than Peruvian and his are more Peruvian than Asian.

Alvaro’s only hurdle was rice, all other measurements were between 5.0 and 5.9. I found this interesting given that his DNAFit report said his carbohydrate tolerance is moderate and he should shoot for lower GI foods, while mine said my tolerance is high and I can get away with a bit more of the high GI foods.

Finally, I found it hilarious that my blood sugar after the gluten-free bread was stellar. I stopped eating bread in 2011 and have eaten gluten-free bread only occasionally – I’d say once a fortnight on average, mainly when eating out. Will I start eating gluten-free bread with reckless abandon? I don’t think so. I still prefer eating vegetables both for taste and health reasons. But I won’t stress too much and let the gluten-free bread happen when it happens.



Sweet potato

Sweet potato

Basmati rice

Basmati rice

Steel cut oats

Steel cut oats

Rolled oats

Rolled oats

Gluten free bread

Gluten free bread

Potato (half dose)

Potato (half dose)

Hot chips

Hot chips

Potato and avocado oil mayonnaise

Potato and avocado oil mayonnaise

If you’re interested in Robb’s new book you can find it here: Wired to Eat.

Food for thought: Reading vs listening

I used to read a lot for fun. Then I decided to go back to uni and my reading turned a lot more academic. At some stage I decided to stop buying physical books and got a Kindle, mainly because it is a pain in the ass to move houses when you have heaps of books. Then I started listening to podcasts and realised I learn way quicker this way. I also enjoy the practicality of audio: I can do it while stretching, cooking, showering, walking, etc. Of course some activities require more concentration than others, but I’ve found I can get away with listening to podcasts while working if what I’m doing is fairly mechanical (or I’m not super interested in what’s playing on my phone).

Recently I started an audible membership, that allows me to download one book per month for “free” (i.e. for the cost of the membership). That’s a good pace for me at the moment because I don’t have a lot of time to listen to stuff and I’m still subscribed to a lot of podcasts.

I’ve noticed this shift from reading to listening not only with books, but also with blog posts. I used to read most of the articles in my feed from start to finish. Now, if there’s a choice of reading or listening (e.g. articles posted in blogs like Precision Nutrition and Mark’s Daily Apple), I disregard the article and listen to the podcast episode instead. If there’s no audio version, I convince myself that I absolutely *need* to read that article, otherwise I just discard it. It might be that my information FOMO is fading off, but I think it’s just that I don’t find the same value in reading anymore. I’ve become a listener.

One thing that I miss, though, is the active part of being a reader, the opportunity to use my imagination in giving a voice and a pace to the words. On the other hand, listening forces me to pay more deliberate attention because audible information is more likely to fade away if not stored in long-term memory; printed words are more “permanent” in that sense. I have also noticed that the reader’s voice, accent and occasional mispronunciation of words have the potential to annoy the heck out of me, in the same way cheap paper or poor font choice would annoy me when reading printed books.

If you haven’t tried listening to podcasts or audiobooks yet, I recommend you try it to see how it goes for you. It can help your productivity and/or appeal more to your learning style.

Food for thought: Moderation for the moderators

If I had 10 cents for every time I’ve heard “everything in moderation”… Actually, it’s more like if I had 10 cents for each time I’ve said it (read: I’m broke). Unlike most dietitians, I don’t advocate moderation because I don’t think it’s the right thing for everyone.

As Gretchen Rubin has noted, there are 2 kinds of people when it comes to behaviour: moderators and abstainers. Moderators find it easy to have 1 square of chocolate whenever they feel like it; abstainers demolish the whole bar if it’s within reach. Needless to say, the strategies that work for each type of person are different.

I’m an abstainer and that’s why I find it easier to create rules for myself and stick to them. I now understand that I can’t ask everyone to do the same, but I can suggest people like me to try using similar strategies.

Craig Ballantyne, whose work on the fitness industry has helped me in the past, also works in the world of habits. I’ve heard him say many times that rules make life easier because you become a person who behaves a certain way all the time, which avoids wasting time fighting against oneself. I agree with this principle, but would add that it only works if you are the kind of person who can stick to rules (typically abstainers, in Gretchen Rubin’s terms).

The other problem with moderation, in my opinion, is that there is no definition or limitations as to what constitutes moderation. From what I’ve seen, people who advocate for moderation normally consume a lot more of crap than what I would consider a moderate amount. Moderation becomes an excuse to overdose on things that they know they shouldn’t be having. I think that it’s helpful to record what you eat in a day (or a few) to have a clear picture of your diet. You might find that what you call moderation looks a lot more like excess.

Final rant: nutritional guidelines typically do not reflect “everything in moderation”. This and other mixed messages are, in my opinion, why there is so much confusion in the topic of nutrition.

Food for thought: Quinoa vs. quinua

Eating quinoa has been increasingly becoming trendy for the past decade or so. When I grew up, quinua (the correct spelling in Spanish, adapted from Quechua) was eaten mainly by highlanders and thus was seen as poor person’s food. It only became fashionable when I was in my early 20s. I believe it was due to the international demand for yet another “superfood”. Since then, countries like Bolivia and PerĂº have been exporting quinua in great quantities, and prices have gone up, even for the locals.

A few days ago I came across this newspiece about increase of quinoa crops in Australia. A couple of things came to mind: 1) exports from countries like mine will drop in the near future, and 2) I wonder if the rushed yield-centered processing of the pseudo-grain will do the same that it apparently does to wheat (i.e. neglecting plant maturation that occurs with traditional farming, and thus making it potentially problematic to health). Only time will tell.

Food for thought: For most questions the answer is “it depends”

A person concerned with her weight recently asked me and another dietitian how much avocado she could eat per day. As always, my answer was “it depends”. Without a context (what does her current diet look like, does she have any medical conditions, what is her metabolism like, etc.) it’s impossible to answer that type of question with a round (or decimal) number.

This reminded me of something that happened more than 10 years ago. I had lost some weight and some girls at work started eating apples with lemon juice (on top of their normal diet) because someone had seen me squeezing lemon juice on an apple (most likely to prevent oxidation) and they assumed that that was the key to weight loss. A great example of how correlation does not mean causation.

Most people are after the magic pill, the ultimate superfood, or the perfect supplement; the ultimate shortcut to optimal health or body composition. The problem is that health is incredibly complex and, in addition, a moving target. I prefer to approach health as a continuum rather than a binary switch. The same principle can apply to foods and lifestyle choices, which are typically more or less healthy for a particular person than an alternative, and not necessarily “healthy” or “unhealthy” per se. My “healthy” can be your “junk”, or vice-versa.

Food for thought: Karmic inflammation

I just came back from a hill sprint session in Sydney Park. After 108 repetitions of a physical meditation that involves the whole body (knees included). After 2 days in a row of training, including back squats both days. There’s no way I could have done that when I was younger.

Paul McCarthy - SydneyPark (cropped)

I started having knee pain when I was a child. My detail-oriented mum noticed that I would get it every time I had tonsillitis, which happened a few times per year in the beginning and once every few weeks until I had my tonsils removed. Unfortunately, the surgery didn’t fix the knee pain, because the inflammation was still there. It became chronic and the pain got more intense over time to the point that some nights I would lay in bed crying, unable to sleep (and I’m not a crier).

My family had a few theories of what caused my pain. Some said it was me throwing myself on the ground and landing on my knees when I was a kid. But how could that become a bigger problem later on if I did it a handful of times when I was very young? Some said it was the taekwondo. But I only did it for a few years in my mid-late 20s.

In my opinion, what was the root of my inflammatory problems was my diet. I did a big change from a Westernised diet to a healthier diet (by conventional wisdom standards) in my mid 20s, which helped tackle some digestion issues and improve my body composition, but didn’t help with inflammation. Reflux got worse, knee pain got worse. It wasn’t until I removed the pro-inflammatory stuff out of my diet that my symptoms disappeared.

I’m not saying that everyone should eat what I eat, but I think it’s sensible to give it a shot. I’m not saying that diet is the only underlying cause of inflammation, but it’s quite possible that what you consistently choose to put in your body can have a big impact in your health. The cause and effect relationship might be difficult to see because your everyday behaviour is habitual, but it adds up. Small consistent habits of the past have shaped your present. It’s like karma. It is karma.

Finally, why hill sprints? Running on grass and uphill are great ways to reduce the load on the joints (see items #13 and 15 here). Additionally, the uneven terrain forces your body out of its comfort zone (learn more about this here).

Food for thought: Eyes on your own plate

I love this advice often given by Liz Wolfe and Diane Sanfilippo in the Balanced Bites podcast. It is very easy to get in the trap of being judgemental about other people’s food choices. It seems this is not constrained to health-conscious people (whatever that means). Everyone has an opinion of what everyone else is eating. If they happen to be eating the exact same meal, then it’s the portion size, whether they mix the components of the meal or not, etc. It’s not easy to let go of this habit but it’s useful to remind yourself to keep your eyes on your own plate, worry (not too much!) about your own food choices and how they affect your health, performance, happiness, etc. The others are adults and are entitled to make their own choices. Also, be polite and refrain from making comments about how disgusting is what other people are eating.

I’m not saying “never ever look at other people’s plates again”. Once again, it all depends on the intention. If you’re following people on social media because their food photos motivate you to eat healthier, inspire you to cook new dishes, or help you find out where’s the best burger in the city, that’s totally fine in my books. But if your intention is plain negative criticism, do yourself a karmic favour and save it for yourself.

PS: As everything else I write on this blog, this post is primarily a reminder to myself.

Food for thought: Old is the new new

I’m old. I’m 37. It’s interesting for me to see that just recently people have started recommending stuff that is not new to me. As a teenager, I wore amber glasses to filter out the blue light from my computer monitor (dad, you were so right!), went on an Atkin-esque diet when conventional wisdom was even more obsessed with low fat than now, and had butter in my coffee (okay, technically the butter was on the soda crackers that I dunked in my coffee, but the butter did end up in my coffee). Sadly, back then there was no internet as we know it now, no blogs, no Instagram. I could have been famous. Now I’m just old.

Food for thought: On belts, nutrition, Buddhism, and debate

In Peru “no tener correa” (have no belt) reflects the inability of people to be cool with being wrong. I have no idea how to express that in English and I have no clue how the saying came about* but I know for sure that “yo no tengo correa” (I don’t have [a] belt). That’s why I don’t like competition (because I hate losing) and I avoid conflict.

It is a mystery that I’ve felt drawn to two areas that require a very sturdy belt, i.e. nutrition and Diamond Way Buddhism. Both areas are highly controversial and, as it happens with Buddhist philosophy, I’m starting to suspect you have to be pretty good at debate if you want to stand out from an academic/Western-idea-of-knowledge point of view. One of the masters in the school of Buddhism I follow, Naropa, was famous because he could win any debate, then take his opponent’s side and win the debate again. I think this not only shows that some people are extremely gifted when it comes to defending a point of view (think politicians and leaders in any field) but also that pretty much any argument can be defended if you have the ability to do so. This is why you can find scientific papers to back up a lot of contradicting claims. Biases not only exist, but clearly dominate some “truths” in human knowledge.

This week I’ve had a few opportunities to test my “lack of belt”. I’ve questioned once again my future in this new career path I’ve chosen to get away from the work I feel no passion about. I’m the kind of person who finishes what they have started. When I did my first uni degree I hated my dad from forcing me to do so but now I appreciate this kind of behaviour can have advantages. I will persevere in this new career path until I’m forced off it. I have the suspicion that meditation will help with training my ego to let go of attachment to stuff, including the need to be right. Let’s see if it pays in the end.

* Update courtesy of my friend Manuel Borja (aka “the master”): the phrase refers to the belts used by Augustine monks who, unlike others, didn’t wear ropes to hold their robes.

Food for thought: Dry July is over… what’s next?

Image from
Image from

So… this is it. July is over, Dry July is over (although you can still donate until August 31st here). I didn’t help raise that much money to support the battle against cancer but I guess that’s what happens when you’re not particularly popular. Big thanks to the generous people who supported me. Rest assured that you’ve made a difference in the life of someone who is dealing with cancer.

Will I do it again next year? Doubt it. I don’t want to ask for more money from the same people. I will definitely support someone else. And I will probably take the month off drinking again. In fact, I might go off the booze in a more permanent basis.

WTF??!! Let me explain… For some reason I’ve had no problem in avoiding gluten (and most grains) for the last 3+ years due to a mild intolerance, but I haven’t been able to give up alcohol even when I’m clearly allergic to it (thanks mum for those Asian genes!). All the effort put in consuming grass-fed beef, pastured poultry, eggs and pork, organic vegetables, etc., is flushed down the toilet every time I drink more than what I can handle.

I thought a month without booze would have stellar effects in my health and/or body composition. Did it work? Body composition-wise, no. Apparently when I drink I don’t ingest enough alcohol calories to make a difference. And the munchies (mostly stress-induced) are there with or without alcohol. Health-wise, I did notice my digestion improved. I just got my annual blood test results back and they’re all good as per usual.

Of course being hangover-free has been a (modest) boost to energy and productivity. I’d like to say it made wonders for my training but the fact is I still suck at that and still haven’t found the magic recovery protocol (is it even possible at my age??).

Have I missed alcohol? To be honest, not that much. I’ve missed cooking with it because I love the flavour it gives to stews and stuff, but I haven’t had any serious cravings for a glass of wine or a bottle of cider. To be fair, I wasn’t really exposed to many heavy drinking situations or free glasses of wine during July, which certainly helped.

Am I ruling alcohol out forever? No. But I want to treat it as a once in a while component of my diet (along with white rice, corn and cheese) rather than 2+ glasses 2+ nights of the week. As I said, I love cooking with alcohol, so I’ll continue using it as an ingredient.