The Science of Nutrition
10-14-2013, 08:50 AM
#102
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Well, look at that. The federal nutrition research over the last 40 years may be bunk.
40 years of federal nutrition research fatally flawed
40 years of federal nutrition research fatally flawed
"When surveyed, a lot of people misreport their caloric intake."
Fortunately, this doesn't render all nutritional research conducted over the past 40 years invalid, only that part of it which was based principally on self-reporting surveys rather than clinical research.
And let's be honest, we all intuitively knew that was the case anyway. When surveyed, people mis-report damned near everything- their discretionary income, the number of past sexual partners they've had, the amount of time they spend watching television, their childrens' class ranking, their influence over purchasing decisions at work, their favorite character in My Little Pony, etc.
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10-14-2013, 12:15 PM
#104
And this invalid data does affect the national health culture and inform the official nutritional guidelines.
Changes in Underreporting and Public Policy Recommendations
In addition to the ubiquity of misreporting, there is strong evidence that the reporting of ‘socially undesirable’ (e.g., high fat and/or high sugar) foods has changed as the prevalence of obesity has increased [12]–[15]. Additionally, research has demonstrated that interventions emphasizing the importance of ‘healthy’ behaviors may lead to increased misreporting as participants alter their reports to reflect the adoption of the ‘healthier’ behaviors independent of actual behavior change [17], [41]. It appears that lifestyle interventions “teach” participants the socially desirable or acceptable responses [17], [42]. As such, the ubiquity of public health messages to ‘eat less and exercise more’ may induce greater levels of misreporting and may explain the recent downward bias in both self-reported EI [20] and body weight [17], [43], especially given that social desirability bias is often expressed in the underreporting of calorically dense foods [44].
Selective misreporting of specific macronutrients has important ramifications for epidemiological research and nutrition surveillance. Heitmann and Lissner (2005) demonstrated that the selective misreporting of dietary fat by groups at an increased risk of chronic non-communicable diseases may result in an overestimated association between fat consumption and disease [45]. If the potentially negative effects of high-fat diets are overestimated due to selective misreporting, current recommendations for fat intake may be overly conservative [45].
In addition to the ubiquity of misreporting, there is strong evidence that the reporting of ‘socially undesirable’ (e.g., high fat and/or high sugar) foods has changed as the prevalence of obesity has increased [12]–[15]. Additionally, research has demonstrated that interventions emphasizing the importance of ‘healthy’ behaviors may lead to increased misreporting as participants alter their reports to reflect the adoption of the ‘healthier’ behaviors independent of actual behavior change [17], [41]. It appears that lifestyle interventions “teach” participants the socially desirable or acceptable responses [17], [42]. As such, the ubiquity of public health messages to ‘eat less and exercise more’ may induce greater levels of misreporting and may explain the recent downward bias in both self-reported EI [20] and body weight [17], [43], especially given that social desirability bias is often expressed in the underreporting of calorically dense foods [44].
Selective misreporting of specific macronutrients has important ramifications for epidemiological research and nutrition surveillance. Heitmann and Lissner (2005) demonstrated that the selective misreporting of dietary fat by groups at an increased risk of chronic non-communicable diseases may result in an overestimated association between fat consumption and disease [45]. If the potentially negative effects of high-fat diets are overestimated due to selective misreporting, current recommendations for fat intake may be overly conservative [45].
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10-14-2013, 12:36 PM
#105
Someone should break the news to Ian Spreadbury that his research isn't science because science has already told us to just eat moderate amounts of everything and everything will be fine.
Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity
Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity
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10-14-2013, 06:24 PM
#107
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What I fail to understand is how faults in the validity of data used to produce statistics affects the underlying validity of recommendations such as (to quote the excerpt): "eat less and exercise more."
Towards the goal of weight loss, improved BMI, etc., that advice remains valid and stands on its own regardless of any offsets or biases in self-reporting data.
Consider the following: Let's say that I survey a thousand people with the questions "Do you smoke, and if so, how much do you smoke per day?"
And let's say that, on average, people under-report their smoking by 50%. So I publish a report saying that "15% of Americans smoke on a daily basis, and on average, consume 10 cigarettes per day." This data turns out to be wrong, because in reality, 30% of Americans smoke on a daily basis, and on average, consume 20 cigarettes per day.
This does not change the validity of my advice that, if you want to decrease your risk of cancer and heart disease, you should stop smoking.
Towards the goal of weight loss, improved BMI, etc., that advice remains valid and stands on its own regardless of any offsets or biases in self-reporting data.
Consider the following: Let's say that I survey a thousand people with the questions "Do you smoke, and if so, how much do you smoke per day?"
And let's say that, on average, people under-report their smoking by 50%. So I publish a report saying that "15% of Americans smoke on a daily basis, and on average, consume 10 cigarettes per day." This data turns out to be wrong, because in reality, 30% of Americans smoke on a daily basis, and on average, consume 20 cigarettes per day.
This does not change the validity of my advice that, if you want to decrease your risk of cancer and heart disease, you should stop smoking.
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10-14-2013, 07:13 PM
#108
What I fail to understand is how faults in the validity of data used to produce statistics affects the underlying validity of recommendations such as (to quote the excerpt): "eat less and exercise more."
Towards the goal of weight loss, improved BMI, etc., that advice remains valid and stands on its own regardless of any offsets or biases in self-reporting data.
Towards the goal of weight loss, improved BMI, etc., that advice remains valid and stands on its own regardless of any offsets or biases in self-reporting data.
Use cocaine
Smoke cigarettes
Host a parasite
Throw up after meals
Eat only McDonald's as long as you maintain a caloric deficit
The issue is not that we can't figure out how to lose weight; the issue is that those various methods all fall onto a continuum in terms of health, efficiency, sustainability (speaking in terms of personal goals, not global ecology), and so on.
No one is disputing that maintaining enough of a caloric deficit will lose weight; the question is whether that advice leads to the most successful outcomes in terms of those other goals (health, efficiency, etc.).
When you consider the nutritional paradigm in terms of a fuller set of goals, then it becomes quite important what kind of data you are using to support your theory. And if invalid data is lending greater support to one particular method of weight loss, then the whole paradigm needs to be reexamined in light of valid data.
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10-14-2013, 07:14 PM
#109
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"eat less exercise more"
One's appetite (or lack thereof) will prevent over-eating if the bodyfat regulation mechanism is working properly. What breaks it is decades of excessive starch consumption causing repeated blood sugar spikes which causes *insulin resistance*.
Lab mice can be made to starve to death even with a lot of bodyfat. Their bodies preferentially consume lean body mass and leave their bodyfat alone.
Lab mice can also be fed the same # of calories but different food, and have the same toys available, but one group will become sedentary and fat while the other active and lean. Nobody is telling the mice to exercise.
The causality is backwards. It's not that eating less and exercising more makes you thin. It's that the factors that cause obesity, cause you to eat more and exercise less.
One's appetite (or lack thereof) will prevent over-eating if the bodyfat regulation mechanism is working properly. What breaks it is decades of excessive starch consumption causing repeated blood sugar spikes which causes *insulin resistance*.
Lab mice can be made to starve to death even with a lot of bodyfat. Their bodies preferentially consume lean body mass and leave their bodyfat alone.
Lab mice can also be fed the same # of calories but different food, and have the same toys available, but one group will become sedentary and fat while the other active and lean. Nobody is telling the mice to exercise.
The causality is backwards. It's not that eating less and exercising more makes you thin. It's that the factors that cause obesity, cause you to eat more and exercise less.
Last edited by JasonC SBB; 10-14-2013 at 07:35 PM.
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10-14-2013, 07:44 PM
#110
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So, just to verify that I understand you correctly; You're saying that, all else being equal, if I reduce my caloric intake by eating less, and increase my caloric expenditure by exercising more, and make no other changes to my diet or lifestyle, that I will NOT lose weight. Correct?
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10-14-2013, 08:22 PM
#111
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Not what I'm saying. Being able to easily reduce your caloric intake is a strong function of your bodyfat setpoint. If you starve yourself you will lose weight. But if you have excess fat and you lower your bodyfat setpoint, your appetite will reduce and you will effortlessly lose fat - i.e. you won't be hungry and miserable as you lose weight.
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12-01-2013, 04:55 PM
#117
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This article basically sums up my opinions and thoughts about content-specific dieting:
Twinkie diet helps nutrition professor lose 27 pounds - CNN.com
Twinkie diet helps nutrition professor lose 27 pounds - CNN.com
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12-01-2013, 06:53 PM
#118
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This article basically sums up my opinions and thoughts about content-specific dieting:
Twinkie diet helps nutrition professor lose 27 pounds - CNN.com
Twinkie diet helps nutrition professor lose 27 pounds - CNN.com
Blasphemy.
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12-03-2013, 11:22 AM
#120
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In case you missed my explanation. The system of hormones Leptin, Insulin, and Ghrelin *make* you eat less (or more) and make you expend more (or less) calories. Yes you can override it, (e.g. by starving yourself, or by force-feeding yourself), but you will lose lean mass and/or be less healthy.
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