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Fat Logic

Upchurch said:
rustypouch said:
Would that "something else" be bad data? From the abstract, it says that the data about food intake was from surveys, so I'm assuming this means it was self reported. People in general are terrible at recalling and reporting what they eat.
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Wrong kind of survey.
The National Health and Nutrition Examination Survey (NHANES) is a survey research program conducted by the National Center for Health Statistics (NCHS) to assess the health and nutritional status of adults and children in the United States, and to track changes over time. The survey combines interviews and physical examinations. The NHANES interview includes demographic, socioeconomic, dietary, and health-related questions. The examination component consists of medical, dental, and physiological measurements, as well as laboratory tests administered by medical personnel
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In other words, self-reported.
 
It's global warming. People today don't have to burn as many calories to maintain body temperature. Either that or Quantum something something.
 
The study got me curious, so I did some more quick digging.

That lead me to looking around on the US government website, and found some info about food availability and consumption.

http://www.census.gov/compendia/statab/cats/health_nutrition/food_consumption_and_nutrition.html

In regards to food availability, in the 1970s, the average was 3200 calories per person, per day. In 2006 it was 3900. Is it more now? Wouldn't surprise me.

The consumption trends I find interesting. http://www.census.gov/compendia/statab/2012/tables/12s0217.pdf People are consuming less red meat and eggs, but more poultry, so the total amount of protein people consume has been pretty stable from 1980 to 2009, with a slight decrease.

The consumption of almost everything else has gone up. Comparing 2009 to 1980, the average American eats about 15 more pounds of cheese, 20 more pounds of fat and oils (mostly in salad and cooking oils), 50 more pounds of wheat and cereals, and 30 more pounds of high fructose corn syrup, (this may not be quite as alarming as the others, and cane and beet sugar consumption has dropped by 20 pounds, but is still a 10 pound increase in sugars) every year.

For some reason the increase in carb intake claimed in the study (10-14%) is significantly lower than the increase claimed by the US government. Granted, the government source I found was from 1980, not 1971, but it doesn't make sense that there would be a smaller increase in a 40 year span than 30 years.

What I don't understand is why the study claims that fat intake has gone down, while the government claims it's gone up. Unless the study is talking about fat from animal/meat sources, which would make sense with the decline of red meat and the rise of poultry. But I didn't see mention of cooking oil in the summary of the study, and I'm too cheap to pay for it to read through.

Both the study and the government numbers showed increased consumption over the last few decades, but the government estimates are higher. The governmental numbers don't seem to take into account waste at home, but rather go by what was purchased. Even still, there is a difference. But waste would account for the discrepancy? That would be a lot.
 
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rustypouch said:
Both the study and the government numbers showed increased consumption over the last few decades, but the government estimates are higher. The governmental numbers don't seem to take into account waste at home, but rather go by what was purchased. Even still, there is a difference. But waste would account for the discrepancy? That would be a lot.
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Just to avoid any confusion, the study used information from the National Health and Nutrition Examination Survey (NHANES), which is conducted by the CDC. The numbers used by the study are government numbers.

I don't know the Census's methodology for this particular set of numbers, but I'm guessing it's probably, you know, the census, which would be closer to the the self-reporting that you're disparaging as faulty data than the more rigorous methodology used by the CDC.
 
Why would the more rigorous methodology used by the CDC be any more useful if it's still a lot of people lying about their eating and exercise habits?


Comment on an earlier bit:
In other words, people today are about 10 percent heavier than people were in the 1980s, even if they follow the exact same diet and exercise plans.
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That 10% number seems way skewed. Maybe 10% of the population is 10% heavier, but I would guess 50% of the population is 25% or more heavier.

My science ? None; other than a stroll down a busy sidewalk and comparative scenes from the 80's..

I can also view comparative group photos and see the same thing...
 
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Skeptical Greg said:
That 10% number seems way skewed. Maybe 10% of the population is 10% heavier, but I would guess 50% of the population is 25% or more heavier.
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You're thinking in terms of total population. They're comparing groups controlled with the same dietary intake and exercise levels.
 
Upchurch said:
Maybe, maybe not. This is only one study. However, from a critical thinking perspective, it cannot be disregarded simply because it does not fit with what you already believe to the case.

The theory must fit the data, not the other way around.
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Very true. One could hypothesize all sorts of things that might affect metabolism, and NOT be captured under calories, macronutrient, and exercise metrics.

Environmental factors, pesticides, stress, concentration of micronutrients, concentration of certain vitamins - heck the prevalence of vitamin and supplement use in adults - hormones, prevalence of common drugs like PPIs and heartburn treatments, the list goes on and on. There are all sorts of things that could feasibly affect metabolism and nutrient absorption.
 
rustypouch said:
What I don't understand is why the study claims that fat intake has gone down, while the government claims it's gone up. Unless the study is talking about fat from animal/meat sources, which would make sense with the decline of red meat and the rise of poultry. But I didn't see mention of cooking oil in the summary of the study, and I'm too cheap to pay for it to read through.
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Low-Fat diet craze, and the increase in low-fat packaged foods.
 
Upchurch said:
Just to avoid any confusion, the study used information from the National Health and Nutrition Examination Survey (NHANES), which is conducted by the CDC. The numbers used by the study are government numbers.

I don't know the Census's methodology for this particular set of numbers, but I'm guessing it's probably, you know, the census, which would be closer to the the self-reporting that you're disparaging as faulty data than the more rigorous methodology used by the CDC.
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Skeptical Greg said:
Why would the more rigorous methodology used by the CDC be any more useful if it's still a lot of people lying about their eating and exercise habits?
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Because how you ask the question, and the specific questions asked, can make a significant difference to the measurements.

For example: My company did a survey a couple of years back, around health-related risks. We asked people two sets of questions.

The first set of questions was very simple: How healthy are you? How healthy do you feel you are relative to your peers? It's a very clear self-reporting question, and it relies on people's perception of themselves and their peers.

The second set of questions specifically asked for the presence of specific medical conditions, hours of exercise per week, height, and weight, alcohol consumption, and whether they smoke. We have risk factors associated with all of those things, and can calculate a score for each respondent.

When we compared the relative values of the two response sets, we found that the "self reporting" questions in the first set were pretty much useless. The distribution was flat - nearly everyone thought they were "relatively healthy". But the calculated scores showed a significant variance. Essentially, the responses for the first question set was almost a straight line, whereas the scores for the second set bounced around all over the place with lots of highs & lows.

Both of those sets of data were collected by survey, and there's the *possibility* that a person might lie for both. But one set of data was considerably more reliable and accurate than the other. I don't personally consider the second set to be "self-reported"... even though people were "reporting" things about their "self"
 
Upchurch said:
Just to avoid any confusion, the study used information from the National Health and Nutrition Examination Survey (NHANES), which is conducted by the CDC. The numbers used by the study are government numbers.

I don't know the Census's methodology for this particular set of numbers, but I'm guessing it's probably, you know, the census, which would be closer to the the self-reporting that you're disparaging as faulty data than the more rigorous methodology used by the CDC.
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Turns out you're right, that if you follow the trail of sources, it leads to the NHANES. Interesting.

I read the explanation at the top of the chart. "In pounds, retail weight, except as indicated. Consumption represents the residual after exports, nonfood use and ending stocks are subtracted from the sum of beginning stocks, domestic production, and imports."

I took that to mean that they calculated the amount sold at retail, and, by extension, the amount consumed.

Unless people are throwing out a lot more food than they used to.
 
Emily's Cat said:
Very true. One could hypothesize all sorts of things that might affect metabolism, and NOT be captured under calories, macronutrient, and exercise metrics.

Environmental factors, pesticides, stress, concentration of micronutrients, concentration of certain vitamins - heck the prevalence of vitamin and supplement use in adults - hormones, prevalence of common drugs like PPIs and heartburn treatments, the list goes on and on. There are all sorts of things that could feasibly affect metabolism and nutrient absorption.
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Don't forget gut flora
 
Skeptical Greg said:
Why would the more rigorous methodology used by the CDC be any more useful if it's still a lot of people lying about their eating and exercise habits?
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:confused: ...because the CDC isn't just relying on what the people report. They are also conducting medical exams. The Census, assuming they are using the standard census method most people are familiar with, are just making out forms for people to fill out and mail back.
 
Emily's Cat said:
Very true. One could hypothesize all sorts of things that might affect metabolism, and NOT be captured under calories, macronutrient, and exercise metrics.

Environmental factors, pesticides, stress, concentration of micronutrients, concentration of certain vitamins - heck the prevalence of vitamin and supplement use in adults - hormones, prevalence of common drugs like PPIs and heartburn treatments, the list goes on and on. There are all sorts of things that could feasibly affect metabolism and nutrient absorption.
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You left out the environmental factors like sitting on the couch and watching TV or playing video games.

Your long list of environmental factors are hardly the main culprit in pre-pubescant children where obesity is a growing epidemic..
 
Emily's Cat said:
For example: My company did a survey a couple of years back, around health-related risks. We asked people two sets of questions.

The first set of questions was very simple: How healthy are you? How healthy do you feel you are relative to your peers? It's a very clear self-reporting question, and it relies on people's perception of themselves and their peers.

The second set of questions specifically asked for the presence of specific medical conditions, hours of exercise per week, height, and weight, alcohol consumption, and whether they smoke. We have risk factors associated with all of those things, and can calculate a score for each respondent.

When we compared the relative values of the two response sets, we found that the "self reporting" questions in the first set were pretty much useless. The distribution was flat - nearly everyone thought they were "relatively healthy". But the calculated scores showed a significant variance. Essentially, the responses for the first question set was almost a straight line, whereas the scores for the second set bounced around all over the place with lots of highs & lows.

Both of those sets of data were collected by survey, and there's the *possibility* that a person might lie for both. But one set of data was considerably more reliable and accurate than the other. I don't personally consider the second set to be "self-reported"... even though people were "reporting" things about their "self"
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Both sets of questions involve self-reporting as described. The first set merely introduces the additional complication of being a more vague set of questions.

The pieces of research that demonstrate how awful people are at self-reporting usually are talking about questions like those in the second set.

Also, I would not refer to lying when discussing erroneous self reporting.
 
rustypouch said:
True, but then what about the increase in oil use?
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It implies that one data set or both may have serious shortcomings. I see speculation about the observed effect being due to gut flora as premature given that what is being revealed is more likely due to observational flaws.
 
Skeptical Greg said:
You left out the environmental factors like sitting on the couch and watching TV or playing video games.
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That's the first thing I thought of.

A lot of things that aren't exercise in name still provided exercise. Even things like getting up to change the videotape. Now, you can sit and stream Netflix and never leave the chair.
 
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