You Can’t Trust What You Read About Nutrition | Hacker News Reader

You Can’t Trust What You Read About Nutrition

fivethirtyeight.com

49 pointskeithpeter16 comments

When I worked in a nutrition department it was common knowledge that people are awful at recalling and reporting what they eat. Obese post-menepousal women in the study would, with a straight face, tell you that all they ate that day was a half cup of green beans. You'd look at their food records and it was physically impossible for them to be alive much less obese on the food they reported they ate. Humans are not only awful at reporting what they ate, they have difficulties even seeing it through the distortions of what they want to see. These are the difficulties associated with nutrition research and one of the reasons why there is so much confusion about what we should eat.

>Obese post-menepousal women in the study would, with a straight face, tell you that all they ate that day was a half cup of green beans.

Maybe that was true and they were trying to lose weight?

The food records were done over repeated visits and long periods of time. Weight, body fat analysis by DEXA scanning, etc. was done as well.

I certainly think these records are quite dubious, even for innocent reasons.

But FWIW: when I started intermittent fasting I didn't even eat much on my non-fast days. It was part of an OCD phase on life tracking so I fetishistically measured and recorded everything I ate or drank[+]. I was working from home so wouldn't eat outside the house.

And even I didn't believe my myfitnesspal records. Except that since I was only eating what was in the house it was pretty clear that I really had only eaten one egg: there were the other 11 in the box.

But wow, without the OCD attitude I don't think it's possible.

[+] And what a waste of effort. A lot of work, little insight. It wasn't just food (and I changed my diet to things I could more tightly control in terms of macros) but weight and sleep and what I bought and how much I spent...a lot of work for very very little insight.

My thinking was that by, say, taking a phone snap of your plate at each meal (some chap in the UK did this a few years ago to convince himself to eat less/better) you could produce a more objective record.

Challenge: can you calculate approximate calorific values from images of food on a plate?

Interestingly, this has been the approach of a dietary study being conducted by a group doing research on a circadian-focused pattern of eating. The study uses a mobile app as part of their distributed clinical trial design. Participants take pictures of their food with only the option of further journaling. Kind of cool.

Here's the website for the trial (& app)...

http://www.mycircadianclock.org/

Here's a video of the principal investigator (Satchin Panda) talking about his research...

https://www.youtube.com/watch?v=-R-eqJDQ2nU

Dissolved sugar is probably invisible or close. Can you see a difference between a glass of Coke and a glass of Diet Coke? One has 140 calories and the other has nominally zero.

That's not to say you couldn't approximate it and tell someone they ate a Twinkie today which is more fattening than the steamed broccoli they had yesterday. And you could probably help people manage their diet better with an app that could do that. But it's always going to be an approximation with a potential for large error in certain cases.

Recognizing food with ~90% accuracy isn't too hard. Getting calories from that is also easy. I'm currently building this into a food tracking app as a side project, with the hardest part being designing a UI that doesn't suck.

For those interested in evidence-based nutrition, I highly recommend https://nutritionfacts.org/

P.S. Dr. Greger's book is a great resource as well. He does a really good job of checking and referencing quality articles from peer-reviewed journals while looking at the balance of the evidence: https://nutritionfacts.org/book/

first link on there is about cholesterol, and is completely incorrect. they are going back and forth between talking about dietary cholesterol and cholesterol levels in the body as if they are interchangeable. this is an incorrect understanding of human biology.

for anyone looking at this site, i'd be very careful about believing anything it says without doing further research for yourself.

Not really "incorrect". Dietary cholesterol does effect cholesterol amounts in the body, in addition to other food intake, hormones etc.

"Might be true given a million other factors" isn't really the sort of truth you're looking for when trying to get advice.

There aren't million other factors. Saying that cholesterol is affected only by saturated fat is not true. just like saying it doesn't affect it at all.

there is no coherent nutrition advice available at the moment, other than observational evidence of various diseases forming when a population is fed an improper diet.

for example, if starchivores like apes are given huge amounts of sugary foods, they will develop atherosclerosis, the same happens if they're given huge amounts of fatty foods. if carnivores were fed huge amounts of fatty foods, they don't get atherosclerosis, only if you do not remove their thyroid gland, if they on the other hand are fed sugary foods, they develop atherosclerosis. so the mechanism involved in absorbing fat and using it (through various types of cholesterol - lipoproteins), seems to be different between the herbivores, omnivores, carnivores. interesting thing about this is that the discrete classification is faulty and that different hormonal balance can give rise to no or different disease.

there's plenty of examples like this one. but it has nothing to do with the individual as population statistic is quite different from needs of an individual.

I would suggest Harvard School of Public Health, which also provides evidence-based advices and, in addition, issues frequent updates.

https://www.hsph.harvard.edu/nutritionsource/what-should-you...

The whole point of the originally linked article is how dubious "evidence" can be.

If we're having a thread on nutrition, I want to ask HN about Kefir (fermented milk/yogurt from Russia/East Europe), whether they have tried it, and why there isn't more interest in it considering it has a lot of health benefits?

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