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People are bad at reporting what they eat. That's a problem for dietary research

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Re: People are bad at reporting what they eat. That's a problem for dietary research

#101

Post by FredPret »

_dark_matter_ wrote: post #79
FredPret wrote: post #75

We're far too generous with what we allow to be called "science". There is no dietary research, because you can't pull off an unbiased dietary study over a meaningful period of time. Practical and ethical problems abound. Maybe one day we can simulate n=10mm people from the neck down for a period of 30 years, and feed half of them bacon and half of them beans, but even that will have the major problems of being a sim…

There are ALL kinds of things we can't run experiments on. Climate, society, evolution, tech development, surgery, and more. We don't throw our hands in the air and say "science here is impossible!". Instead we roll up our sleeves and develop more and better causal inference models that improve over time.

OK, name such an approach in nutrition that doesn't already fall under regular biology.

The reason we can do science on some things without doing experiments is that there's lots of hard, unambiguous data about relatively much simpler systems.

Getting good data on the extremely complex thing that is homo sapiens is just not feasible, unless you're studying specific chemical reactions in the gut, in which case it'll take an extremely long time to figure out an actual dietary recommendation.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#102

Post by fortran77 »

There's have been several studies, well researched and cited, where people who claim to be "diet resistant" are given metabolic markers "double labeled water" that will accurately show caloric intake.

For example:

https://www.nejm.org/doi/full/10.1056/NEJM199212313272701

and

https://journals.physiology.org/doi/full/10.1152/ajpendo.200...

In the NEJM article they note that every single person who claimed to be "diet resistant" was lying about food intake.

> The main finding of this study is that failure to lose weight despite a self-reported low caloric intake can be explained by substantial misreporting of food intake and physical activity. The underreporting of food intake by the subjects in group 1 even occurred 24 hours after a test meal eaten under standardized conditions. In contrast, values for total energy expenditure, resting metabolic rate, thermic effect of food, and thermic response to exercise were comparable with those of obese subjects in group 2 who did not report a history of diet resistance.

and

> In addition to their greater degree of misreporting, the subjects in group 1 used thyroid medication more often, had a stronger belief that their obesity was caused by genetic and metabolic factors and not by overeating, and reported less hunger and disinhibition and more cognitive restraint than did the subjects in group 2. Subjects presenting for weight-control therapy who had these findings in association with a history of self-reported diet resistance would clearly convey the impression that a low metabolic rate caused their obesity.

Calories-in/Calories-out is true for everyone, and everyone can lose weight by putting down his fork.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#103

Post by bluGill »

chikere232 wrote: post #68
bluGill wrote: post #22

Earlier quoted context omitted.

I have long said there are two kinds of diet studies: those that don't apply to you because you are not confined to a hospital bed or prison cell; and those that conclude despite our best effort we couldn't get people to eat their assigned diet.

So what you're saying there's a great business opportunity in people paying to get locked in a diet-cell?

Maybe, though I suspect there are probably a lot of laws around what you can and cannot do so better get several good lawyers to check what the laws really are around this. Drug treatment programs often work like this so that is the first place to look for laws to watch out for.

I've heard of other attempts at things like this. Generally you are not locked into a cell, you are removed to a very remote location by bus so that if you want to leave you have to go through a formal withdrawal process - while waiting for the bus - during which they convince you to stay). They then not only control your diet they also give you exercise (often lead by military drill instructors) thus being a healthier environment than a diet cell. I have no idea how much money they make.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#104

Post by ApolloFortyNine »

aziaziazi wrote: post #29

For those that "track and weight everything" (how ?) do you manage ?: - sauces you make yourself? I often mix some different oils, mustard, seeds, miso, bit of leamon juice and spices… but weighting and logging everything will take 3x the time to do the sauce itself - different cooking time in one receive : oignons going first, tomato sauce in the middle and parsley at the end (but still cook a bit with residual heat…

In what you listed under making a sauce, only mayo and the oils need to be weighed (unless it's some ridiculous amount of seeds). If you don't already know whats high calorie you learn quickly, in reality the average person gets the bulk of their calories from probably less than 10 items (flour/rice/chicken/etc).

Re: People are bad at reporting what they eat. That's a problem for dietary research

#105

Post by bluGill »

BoxFour wrote: post #36
bluGill wrote: post #17

Earlier quoted context omitted.

most people are embarrassed about the truth. So they will over report vegetables while not mentioning how much alcohol or tobacco they had (or illegal drugs which the study probably legally must report to the police). Or a self proclaimed vegetarian will not report meat they ate despite their claim. fat people will report they skipped desert.

Why would that be a problem for reporting relative results if the entire population is doing that? If everyone is under-reporting their alcohol consumption, that seems fine. The absolute numbers will be way off, the relative numbers to their peers won't.

Statistics can do a lot to find data from noise like this, but it is still noise. The biggest issue is nobody knows what variables are important, which are correlated, and so on.

Edit: there is another issue I forget until now: time. Statistically I have several more decades of life left. So even if you get accurate results of my meals yesterday, you need to report when I died, and you probably won't have the meals for the rest of my life. Did some meal I at when I was 10 have a big effect on my life? For that matter if I know you are tracking just one day's meals I will probably eat what I think is better and that doesn't tell you anything about what I eat the rest of the time.

It is easy to track people who have had a heart attack - they are likely to die of another heart attack in a few years so the study times are short. However does having had a heart attack mean either genetic difference such that your results only apply to a subset of the population, or perhaps some other factor of having had a heart attack.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#106

Post by beezlebroxxxxxx »

robertlagrant wrote: post #98
beezlebroxxxxxx wrote: post #70

Earlier quoted context omitted.

Counting works for people because it quantifies their food intake. For many people, that's an effective way to overcome a learned idea that portions should be huge, or that feeling hungry has to be addressed immediately, or that feeling "full" has to be constant. It's not perfect, and I don't recommend it to people with an ED history; however, after about a month or 2 of doing it, it can really change how you look at…

> I don't recommend it to people with an ED history Your daily reminder that ED means more than one thing.

The little blue pill is probably in MyFitnessPal if one really wants to track all their macros.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#107

Post by augustk »

llm_nerd wrote: post #89
damnesian wrote: post #40

This is why sleep studies are conducted in clinics, not left to patients to self-report. they want accurate data? They will need to conduct a real study, portion the meals out themselves, give people a schedule.

Such studies do exist - randomized feeding trials. In these studies the participants are provided all meals and snacks, and sometimes are under constant surveillance for weeks and sometimes months on end. https://pubmed.ncbi.nlm.nih.gov/39134209/ Obviously such studies are far more invasive and expensive to run than the classic "fill out of a survey" observational study [1], so they tend to be the outliers. But they…

Prisons seem like good places to make these kind of studies.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#109

Post by jjcob »

giantg2 wrote: post #72

Seems like a decent use of AI if we could use something like Glass to scan the label and plate to estimate calories and stuff. You could even record those portions to be used for audit.

ChatGPT does a surprisingly good job of estimating calories from a picture of your plate. Especially if you add details that are hard to tell from the picture.

Re: People are bad at reporting what they eat. That's a problem for dietary research

#110

Post by Havoc »

It’s also just really hard unless you live off packaged meals or only eat thing that are isolated.

Something like a curry cooked in kitchen and shared among a family is a complete black box as to who got how many calories. Maybe one person got a different ratio of rice to curry. Or this family likes a sweeter type of curry etc

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