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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

#21

Post by FriedrichN »

elektrolite wrote: post #11
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.

I think being consistently inaccurate helps. If you always get the same thing at a certain restaurant, you can start by giving your best estimate of the calories in that meal. Then if your average weight doesn't move in the direction you want you can adjust your target calories to compensate.

That probably doesn't work either unless they work in an automated fashion. Did the chef put two or three dashes (official SI unit) of this or that on your meal? A a "dash" or "splash" or "spritz" of certain things can easily mean 100-200 kcal. And if you deal with things like meat, maybe the cut you get today is more or less lean than what you got last week.

I think tracking calories for a couple of weeks can be very enlightening for a lot of people, granted you don't have a personality type where this can get you into trouble. But for the long haul it's not really useful or even feasible, you're better off getting to know what sort of way of eating suits you best and how to correct if you're getting off course. Anyone can stick to a very strict regime for three months, but the trick is to stick to a proper diet you can enjoy for three decades and then three decades more.

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

#22

Post by bluGill »

f1shy wrote: post #2

Just a couple of days ago, I wrote I automatically flag any submission with any kind of "dietary" studies. I'm not saying there is no one study well done, but doing it well, is just (almost) impracticable. Not only the people have literally no idea what they eat, they forget and misreport, also a human living normal life in the society has just TOO MANY variables. There is no way to keep the other variables like, spo…

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.

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

#23

Post by tomrod »

lm28469 wrote: post #18

> Is coffee good for you? What about wine or chocolate? Scientists trying to answer these questions There is a virtually infinite amount of cofounding variables, genetics, meal timing, fitness level, sedentarity, &c. . It's a 80/20 type of problem, do the 80, forget about the 20, you'll never be able to get your answers anyways. If you look and feel like shit you're most likely eating like shit. If you look and feel…

You reduce the uncertainty of the remaining 20 by substantially increasing sample size across a randomly selected sample.

Unfortunately for these studies you have multiple selection criteria that are nonrandom:

(1) interest in the study

(2) adherence to protocol of the study

(3) reporting back in

If nutrition science wants to be serious, their N should not be in the 10s but rather the 10,000s.

That has an expense, but for important things it is absolutely the right thing to do.

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

#24

Post by Turneyboy »

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.

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

#25

Post by pplonski86 »

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.

It takes some effort, but there’s a lot to gain. When I track what I eat and keep my daily calories in check, I feel much better. If I’m unsure of the exact calorie count, I’ll estimate a bit higher - around 1.2x.

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

#27

Post by NoboruWataya »

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.

Yeah, I have tried a few times to keep track via Cronometer but I can never keep it up. Eating out is the killer, as you say. I find I often don't even have a frame of reference for estimating the amount of calories. With the amount of sauces and oil that go into a lot of stuff, I feel like a lot of things could as easily be 1,200 calories as 500 calories.

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

#28

Post by oersted »

thefz wrote: post #12

Everything needs to be weighted on a precise scale, every ingredient and not just the macros. On top of that the reported nutrition values on labels can be wrong by a large margin so for not whole foods, we introduce an error. This is why calorie counting is ballparking to get us a general idea, and not a precise science.

I find the way we measure calories very interesting: place the food in a metal box filled with oxygen, immerse the box in water, make the food explode so that it combusts completely, and finally measure how much the water heats up.

Rather crude and fun, but that's it, see Bomb Calorimeter. I guess it makes sense in retrospect, how else would you do it?

They usually just measure standard basic ingredients, then you roughly match them to your recipe and add it up. No wonder food labelling is just a ballpark.

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

#29

Post by aziaziazi »

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)

- Leftovers nutrients decrease with time

- counting how much you take of a meal shared with others, especially when you serves yourself multiple time

- different species/cultivation methods like the rustic small and dense cucumber from your neighbor and the spongy one from the supermarket in January

I have the feeling that might have been easy at some point in my life when I lived alone and mostly eat packaged food and raw vegetable that looked like clones but not when I share my meal, cook a lot more raw un-barcoded aliments and gained confidence to dose "by the eye" without recipes.

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

#30

Post by Mountain_Skies »

The benefits of the Minnesota Starvation Study were that both food intake and physical activity could be accurately tracked. If we had a draft and there were conscientious objectors, would similar studies be possible as alternative service? I suspect that our ethical concerns now are greater than they were back then, so maybe it wouldn't be possible to conduct.
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