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

#151

Post by bluGill » Tue, Jan 21, 2025, 2:56 PM UTC

BoxFour wrote: post #58

liveoneggs wrote: post #49

Earlier quoted context omitted.

All of those headlines are based on meta-studies putting together 100 junk studies, based on bad data, which then informs actual medicine and health trends and American X Association and... For your specific example - "morning coffee" could be anything from plain espresso shot to full 600+ calorie starbucks "coffee" but the meta-study-machine will lump them together. It's kind of like feeding all of reddit's comments…

> "morning coffee" could be anything from plain espresso shot to full 600+ calorie starbucks "coffee" but the meta-study-machine will lump them together. You're inadvertently proving my point, though. If morning caffeine is correlated with longevity, regardless of the vehicle/extra sugar/etc and controlling for the easy usual circumstances like income, that's pretty useful information!

But if sugar is worse by more than caffeine is good your study is in trouble. Or maybe it works but it is harmful because people who don't like coffee are going to buy the bad sugar drinks trying to get the good coffee down.

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

#152

Post by watwut » Tue, Jan 21, 2025, 2:57 PM UTC

everdrive wrote: post #81

A lot of people seem to have a purely emotional relationship with resources which logic doesn't seem to be able to penetrate. Food and finances seem similar here. For years I tried to get my wife to stick to a grocery budget. That is, we have $n per week for all groceries. She'd blow badly over the limit every time. "But we needed [food]" or "These were toiletries, so they don't _count_ as groceries." Ultimately we n…

> they struggle with actually putting it into action [...] conceding to their cravings

The trouble is that people who have no problems to do this ... are the ones at risk for anorexia. They lack the instincts that make the rest of us safe from that particular hell.

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

#153

Post by taeric » Tue, Jan 21, 2025, 2:58 PM UTC

wnorris510 wrote: post #130

I've done research in this space for many years at Google AI and now at SnapCalorie. The thing I find interesting is how confident people are in their ability to estimate portion size visually, and in truth how wrong they all are. We published in CVPR (top peer reviewed academic conference for computer vision) and people are on average off by 53% and even trained professionals are still off by 40%. Basically if you w…

This goes a long way to further convince me that it is portion sizes in the US. Having traveled, it is quite absurd to see the difference in standard order sizes.

Even for zero calorie things like water and unsweetened teas/coffees. You just get smaller cups. I'm not even sure you can get a US large in Japan for most drinks?

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

#154

Post by everdrive » Tue, Jan 21, 2025, 3:00 PM UTC

watwut wrote: post #152

everdrive wrote: post #81

A lot of people seem to have a purely emotional relationship with resources which logic doesn't seem to be able to penetrate. Food and finances seem similar here. For years I tried to get my wife to stick to a grocery budget. That is, we have $n per week for all groceries. She'd blow badly over the limit every time. "But we needed [food]" or "These were toiletries, so they don't _count_ as groceries." Ultimately we n…

> they struggle with actually putting it into action [...] conceding to their cravings The trouble is that people who have no problems to do this ... are the ones at risk for anorexia. They lack the instincts that make the rest of us safe from that particular hell.

They're just acceding to an even greater emotional pressure; they're certainly not taking a purely sober and intellectual view of calories and health.

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

#155

Post by zeroonetwothree » Tue, Jan 21, 2025, 3:02 PM UTC

taeric wrote: post #153

wnorris510 wrote: post #130

I've done research in this space for many years at Google AI and now at SnapCalorie. The thing I find interesting is how confident people are in their ability to estimate portion size visually, and in truth how wrong they all are. We published in CVPR (top peer reviewed academic conference for computer vision) and people are on average off by 53% and even trained professionals are still off by 40%. Basically if you w…

This goes a long way to further convince me that it is portion sizes in the US. Having traveled, it is quite absurd to see the difference in standard order sizes. Even for zero calorie things like water and unsweetened teas/coffees. You just get smaller cups. I'm not even sure you can get a US large in Japan for most drinks?

I don’t see why it would be bad to get more water to drink

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

#156

Post by everdrive » Tue, Jan 21, 2025, 3:03 PM UTC

mmooss wrote: post #143

everdrive wrote: post #81

A lot of people seem to have a purely emotional relationship with resources which logic doesn't seem to be able to penetrate. Food and finances seem similar here. For years I tried to get my wife to stick to a grocery budget. That is, we have $n per week for all groceries. She'd blow badly over the limit every time. "But we needed [food]" or "These were toiletries, so they don't _count_ as groceries." Ultimately we n…

> For whatever your metabolism, and whatever your category of calories, fewer calories will still produce weight loss. I thought that wasn't true, that the human body stores and burns calories at varying rates based on many signals, and that our bodies or some bodies effectively conserve weight or caloric stores at a certain level.

The body can compensate at the margins. Eat 5 fewer calories per day and you will see zero change. Eat 500 fewer calories per day, consistently every day, and you will absolutely see changes. (I'm not actually suggesting that it would be _healthy_ or advisable to drop your diet by 500 calories -- just pointing out that the body cannot compensate indefinitely.)

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

#157

Post by Mathnerd314 » Tue, Jan 21, 2025, 3:03 PM UTC

amelius wrote: post #53

Can't this be solved with camera plus AI? I'd be surprised if some startup isn't already working on it.

There are apps, but they are incredibly inaccurate. For starters, they don't recognize the food right. Usually you have to pick from a menu of 10 items. Then they have to estimate a 3D quantity (volume) from a 2D image, then they have to estimate the density... the amazing thing though is despite all this, they are still more accurate than recall diaries.

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

#158

Post by [deleted] » Tue, Jan 21, 2025, 3:04 PM UTC

LPisGood wrote: post #132

wnorris510 wrote: post #130

I've done research in this space for many years at Google AI and now at SnapCalorie. The thing I find interesting is how confident people are in their ability to estimate portion size visually, and in truth how wrong they all are. We published in CVPR (top peer reviewed academic conference for computer vision) and people are on average off by 53% and even trained professionals are still off by 40%. Basically if you w…

>and even trained professionals are still off by 40% I find this very hard to believe, unless the term “trained professional” is quite broad. When I was much more into fitness and weighed every meal to the gram, I could tell if a bowl of cereal was a serving to within a gram or two.

[deleted]

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

#159

Post by taeric » Tue, Jan 21, 2025, 3:04 PM UTC

zeroonetwothree wrote: post #155

taeric wrote: post #153

Earlier quoted context omitted.

This goes a long way to further convince me that it is portion sizes in the US. Having traveled, it is quite absurd to see the difference in standard order sizes. Even for zero calorie things like water and unsweetened teas/coffees. You just get smaller cups. I'm not even sure you can get a US large in Japan for most drinks?

I don’t see why it would be bad to get more water to drink

I didn't mean to imply it was. My point was that everything is smaller.

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

#160

Post by wnorris510 » Tue, Jan 21, 2025, 3:04 PM UTC

LPisGood wrote: post #132

wnorris510 wrote: post #130

I've done research in this space for many years at Google AI and now at SnapCalorie. The thing I find interesting is how confident people are in their ability to estimate portion size visually, and in truth how wrong they all are. We published in CVPR (top peer reviewed academic conference for computer vision) and people are on average off by 53% and even trained professionals are still off by 40%. Basically if you w…

>and even trained professionals are still off by 40% I find this very hard to believe, unless the term “trained professional” is quite broad. When I was much more into fitness and weighed every meal to the gram, I could tell if a bowl of cereal was a serving to within a gram or two.

If you have a known bowl and fill it to a known position every day with the same type of food, then you can probably do better than the average for that specific meal. In our research we've found a majority of calories for most people come from when they're eating out and consuming new dishes where they don't know the ingredients or portion sizes.

In the study we gave people a variety of dishes to make their estimate on, some they were familiar with, some they were not.

The professionals were nutritionists who had trained in portion size estimation and were shown 2D images on a computer screen.

For what it's worth, we've had a lot of people who have claimed to be very accurate at portion size estimation from a long history of using a kitchen scale. We've paid many of them to do a quiz to see if they're above average accuracy and they have almost always ended up around 40% accuracy or worse.