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

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

#31

Post by yurishimo » Tue, Jan 21, 2025, 1:15 PM UTC

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…

For sauces, I either use a bottled sauce if I really want to stick to macros, or I try to make the exact same recipe each time and then I can select my previously created logged item in the diet app.

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

#32

Post by graemep » Tue, Jan 21, 2025, 1:16 PM UTC

bluGill wrote: post #17

BoxFour wrote: post #3

Does this actually pose an issue for most studies? This seems like it would be an issue for any studies relying on absolute food consumption being accurate. Most studies I come across frame their findings in relative terms (likely for this very reason): Individuals who engage in more of X compared to their peers show a correlation with outcome Y. For example, if you’re trying to determine whether morning coffee consu…

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.

I came across a comment as a humorous rule of thumb for this.

1. If you ask someone who much the drink double the answer 2. If you ask them how much the smoke, multiply the answer by five 3. If you ask them how often they have sex, divide the answer by 10.

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

#33

Post by jjj123 » Tue, Jan 21, 2025, 1:16 PM UTC

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…

For me I mostly just try to log the high macro and/or calorie items. Like if I make a Caesar dressing I’m mostly counting the oil and if I’m being really meticulous I’ll measure the Parmesan and anchovy content. But I’ll ignore the 2tbsp lemon juice, garlic, mustard, etc. since it’s counting so little towards the totals I care about.

If you’re trying to measure your vitamin intake this may not work for you, though.

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

#34

Post by BoxFour » Tue, Jan 21, 2025, 1:17 PM UTC

Turneyboy wrote: post #24

BoxFour wrote: post #3

Does this actually pose an issue for most studies? This seems like it would be an issue for any studies relying on absolute food consumption being accurate. Most studies I come across frame their findings in relative terms (likely for this very reason): Individuals who engage in more of X compared to their peers show a correlation with outcome Y. For example, if you’re trying to determine whether morning coffee consu…

You are assuming that the underreporting will be uniform. In reality people may be underrporting things they are embarrassed about and maybe even overreporting the opposite. This is a flaw in the data that is much harder to account for.

Why would that be a problem for reporting relative results if everyone is under-reporting things they're embarrassed about and over-reporting the opposite?

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

#35

Post by IanCal » Tue, Jan 21, 2025, 1:18 PM UTC

xnorswap wrote: post #13

TypingOutBugs wrote: post #6

I try calorie count with My Fitness Pal and holy shit it’s a lot of effort. Eat out and you’re screwed (estimated at best). When you include sauces and oils etc it’s really hard to be accurate in the best of times, and it’s just a pain to keep on top of. Best option is to avoid any so you don’t have to count. I imagine almost everyone will add bad data in a study at some point with the best of intentions.

> Best option is to avoid any so you don’t have to count This is why one of the best ways to lose weight is to just keep a food diary / count calories. You don't need any special / fad diet, just the act of trying to keep a note of everything you eat will cause you to stop and think, "I don't need to eat this".

(this tip works with finances too)

You can give yourself an ability akin to time travel by writing things down first.

If I write down the calories afterwards, I get the "oh, I shouldn't have done that" feeling at times. I'd like a little time travel button that takes me back to before I did, and let me adjust my behaviour and run through the situation again. If I write it down first I get to have the "oh, that's not worth it" feeling up front and decide to do something else.

This made a big difference for me, both lowering what I was eating and making me happier about the choices I made.

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

#36

Post by BoxFour » Tue, Jan 21, 2025, 1:18 PM UTC

bluGill wrote: post #17

BoxFour wrote: post #3

Does this actually pose an issue for most studies? This seems like it would be an issue for any studies relying on absolute food consumption being accurate. Most studies I come across frame their findings in relative terms (likely for this very reason): Individuals who engage in more of X compared to their peers show a correlation with outcome Y. For example, if you’re trying to determine whether morning coffee consu…

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.

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

#37

Post by valval » Tue, Jan 21, 2025, 1:19 PM UTC

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…

Tracking and weighing everything is a massive waste of time and energy. There are no obese animals (humans included) in the wild. Just stop eating the wrong things.

I maintain a muscular 225 by eating dairy, eggs, and meat. If I want to drop down to 215, I drop dairy.

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

#38

Post by Mountain_Skies » Tue, Jan 21, 2025, 1:19 PM UTC

pards wrote: post #8

> many studies of nutritional epidemiology that try to link dietary exposures to disease outcomes are founded on really dodgy data I wonder if the data are always skewed in a particular direction. For example, do people typically underreport junk food and overreport salads? Or do they omit entire meals? Or snacks?

While far from being a potential silver bullet, I do wonder if continuous glucose monitoring could help with this. Your food log shows you didn't eat anything between noon and six in the evening but the glucose monitor shows a spike at 2PM? Your diet app could ask if you forgot to log something around that time. Maybe you want for a long walk aside while it was cold and that was the cause. Unless the question is asked, the tracking data for that time period will be questionable.

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

#39

Post by Drakim » Tue, Jan 21, 2025, 1:19 PM UTC

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…

I bought myself a food weight to have at the kitchen but just like you I struggled with all the minor things that gets added in rapid succession. The trick is to get good enough at estimating within reason, and focus on one aspect such as calories.

Figure out what one table spoon of oil contains, and when you make a sauce use a table spoon while pouring to count roughly how much oil you are putting in.

For shared meals, or self-restricted portions, I just add the entire meal upfront to my book-keeping, and then after are are done eating I subtract what I didn't eat.

You don't need to keep track of the family history of your cucumbers.

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

#40

Post by damnesian » Tue, Jan 21, 2025, 1:19 PM UTC

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.