5 Nutrition and/or Food Research Blogs I Like to Read

I’ve written a bit here over the years about nutrition research and my own general journey with weight management, but I realized I’ve only really referred in passing to the people who I read when I want to catch up on the field. I figured this was a pretty good time to do a post on that.

  1. For all things vegan: Anyone who followed my old old blog knows that I actually spent several years as a vegan. I eventually gave it up, but I still like to read up what’s going on in the world of plant based nutrition. Ginny Messina (aka the Vegan RD) is a registered dietitian who is a vegan primarily for ethical reasons. As such, she uses her dietitian training to help vegans be as healthy as possible, while also helping lead the charge for veganism to be more evidenced based when they stray out of ethics and in to nutrition claims. She writes critiques of other vegans work if she feels they overstate the evidence, and she even coauthored a book called “Even Vegans Die“. Overall a pretty awesome example of someone who advocates for a particular diet while also adhering to evidence.
  2. For the ancestral health crowd: If you’re paleo or just interested in how our evolutionary history influences how we think about food, Stephan Guyenet is a must read. A neuroscientist who specializes in obesity related research, his research focus is on why we overeat and what we can do about it. His book The Hungry Brain is one of the most well balanced science based nutrition books I’ve ever read, and has received quite a bit of praise for being honest and evidence based.
  3. For deep dives in to the science: There are not many bloggers that I read that make me go “holy crap did this person dig deep in to this paper”, but CarbSane is one blogger who gets that reaction from me on nearly every post. She doesn’t just read papers and give you the gist, she posts tables, cites other literature, and is basically a blog equivalent of a nutritional biochemistry class. She is probably the person most responsible for making me aware of the problem of misreprecitation in nutrition science, because she has the patience, knowledge and wherewithal to figure out exactly what commonly cited papers do and do not say. Oh, and she’s lost over 100 lbs too, so she actually has a good eye for what is and isn’t useful for real people to know. For a taste of what she does, try her posts on the “Biggest Loser Regain Study” that made headlines.
  4. For weight management and health policy: There’s really a bit of a tie here, as I really like both Yoni Freedhoff’s Weighty Matters blog and Darya Rose’s Summer Tomato for this topic.  Freedhoff is a Canadian MD who runs a weight loss center, and he blogs from the medical/health policy perspective. His book “The Diet Fix” covers evidence based ways of making any diet more effective, and he encourages people to take the approach (vegan, low carb, paleo, etc etc) that they enjoy the most. Darya Rose is a neuroscientist who also gives advice about how to make your “healthstyle” more practical and easier to stick to,  and her book “The Foodist” is on the same topic. I like them because they both continuously emphasize that anything too difficult or complicated is ultimately going to be tough to maintain. It’s all about making things easier on yourself.
  5. For those in the greater New Hampshire area: Okay, this ones pretty region specific, but the Co-op News blog from the Hanover Co-op has a special place in my heart. An online version of a newsletter that’s been going since 1936, it features frequent posts from my (dietitian) cousin and my (incredible chef) uncle. It’s a great place to check out if you need advice on anything from using up summer vegetables to figuring out if macaroni and cheese is okay to eat. It also serves to remind me that I should invite myself over to their house more often. That food looks awesome.

Bonus round: if your looking for some one off reads, this week I read this takedown of the science in the vegan documentary “What the Health” and enjoyed it. I also liked this paper that reviewed the (now infamous) Ancel Keys “7 Countries Study” and shed some light on what the original study did and did not say.

Of course if you have a favorite resource, I’d love to hear it!

Blood Sugar Model Magik?

An interesting new-to-me study came on my radar this week “Personalized Nutrition by Prediction of Glycemic Responses” published by Zeevi et al in 2015. Now, if you’ve ever had the unfortunate experience of talking about food with me in real life, you probably know I am big on  quantifying things and particularly obsessed with blood sugar numbers. The blood sugar numbers thing started when I was pregnant with my son and got gestational diabetes. 4 months of sticking yourself with a needle a couple of times a day will do that to a person.

Given that a diagnosis of gestational diabetes is correlated with a much higher risk of an eventual Type 2 diabetes diagnosis, I’ve been pretty interested in what effects blood sugar numbers. One of those things is the post-prandial glucose response (PPGR) or basically how high your blood sugar numbers go after you eat a meal. Unsurprisingly, chronically high numbers after meals tend to correlate with overall elevated blood sugar and diabetes risk. To try and help people manage this response the glycemic index was created, which attempted to measure what an “average” glucose response to particular foods. This sounds pretty good, but the effects of using this as a basis for food choices in non-diabetics have been kind of mixed. While it appears that eating all high glycemic index foods (aka refined carbs) is bad, it’s not clear that parsing things out further is very helpful.

There are a lot of theories about why glycemic index may not work that well: measurement issues (it measures an area under a curve without taking in to account the height of the spike), the quantities of food eaten (watermelon has a high glycemic index, but it’s hard to eat too much of it calorie-wise), or the effects of mixing foods with each other (the values were determined by having people eat just one food at a time). Zeevi et al had yet another theory: maybe the problem was taking the “average” response. Given that averages can often hide important information about the population they’re describing, they wondered if individual variability was mucking about with the accuracy of the numbers.

To test this theory, they recruited 800 people, got a bunch of information about them, and hooked them up to a continuous glucose monitor and had them log what they ate. They discovered that while some foods caused a similar reaction in everyone (white bread for example), some foods actually produced really different responses (pizza or bananas for example). They then used factors like BMI, activity level, gut microbiome data to build a model that they hoped would predict who would react to what food.

To give this study some real teeth, they then took the model they built and applied it to 100 new study participants. This is really good because it means they tested if they overfit their model….i.e. tailored it too closely to the original group to get an exaggerated correlation number. They showed that their model worked just as well on the new group as the old group (r=.68 vs r=.70). To take it a step further, they recruited 26 more people, got their data, then feed them a diet predicted to be either “good” or “bad” for them.  They found overall that eating the “good” diet helped keep blood sugar in check as compared to just regular carbohydrate counting.

The Atlantic did a nice write up of the study here, but a few interesting/amusing things I wanted to note:

  1. Compliance was high Nutrition research has been plagued by self reporting bias and low compliance to various diets, but apparently that wasn’t a problem in this study. The researchers found that by emphasizing to people what the immediate benefit to them would be (a personalized list of “good” and “bad” foods, people got extremely motivated to be honest. Not sure how this could be used in other studies, but it was interesting.
  2. They were actually able to double blind the study Another chronic issue with nutrition research is the inability to blind people to what they’re eating. However, since people didn’t know what their “good” foods were, it actually was possible to do some of that for this study. For example, some people were shocked to find that their “good” diet had included ice cream or chocolate.
  3. Carbohydrates  and fat content were correlated with PPGR, but not at the same level for everyone At least for glucose issues, it turns out the role of macronutrients was more pronounced in some people than others. This has some interesting implications for broad nutrition recommendations.
  4. Further research confirmed the issues with glycemic index  In the Atlantic article, some glycemic index proponents were cranky because this study only compared itself to carb counting, not the glycemic index. Last year some Tufts researchers decided to focus just on the glycemic index response and found that inter-person variability was high enough that they didn’t recommend using it.
  5. The long term effects remain to be seen It’s good to note that the nutritional intervention portion of this study was just one week, so it’s not yet clear if this information will be helpful in the long run. On the one hand, it seems like personalized information could be really helpful to people…it’s probably easier to avoid cookies if you know you can still have ice cream. On the other hand, we don’t yet know how stable these numbers are. If you cut out cookies entirely but keep ice cream in your diet, will your body react to it the same way in two years?

That last question, along with “how does this work in the real world” is where the researchers are going next. They want to see if people getting personalized information are less likely to develop diabetes over the long term. I can really see this going either way. Will people get bored and revert to old eating patterns? Will they overdo it on foods they believe are “safe”? Or will finding out you can allow some junk food increase compliance and avoid disease? As you can imagine, they are having no trouble recruiting people. 4,000 people (in Israel) are already on their waiting list, begging to sign up for future studies. I’m sure we’ll hear more about this in the years to come.

Personally, I’m fascinated by the whole concept. I read about this study in Robb Wolf’s new book “Wired to Eat“, in which he proposes a way people can test their own tolerance for various carbohydrates at home. Essentially you follow a low to moderate carbohydrate paleo (no dairy, no legumes, no grain) plan for 30 days, then test your blood glucose response to a single source of carbohydrates every day for 7 days. I plan on doing this and will probably post the results here. Not sure what I’ll do with the results, but like I said, I’m a sucker for data experiments like this.