Author Topic: Any science-based article summarizing a healthy diet?  (Read 4293 times)

0 Members and 1 Guest are viewing this topic.

Online CarbShark

  • Poster of Extraordinary Magnitude
  • **********
  • Posts: 11966
Re: Any science-based article summarizing a healthy diet?
« Reply #60 on: September 27, 2018, 09:36:17 PM »
These epidemiological studies are observations that show correlations. They are not experiments. They are not the scientific method.

They have validity but by themselves are not sufficient. Their observations of correlations need to be confirmed in RCTs.

By their very nature, it’s impossible, even in theory, to do RCTs (random controlled trials) with dietary manipulations.  How are you going to be able randomly allocate one group to consuming whole-grain foods and another group to avoiding them, and actually have the groups persist with them for the years or decades necessary to determine if there’s a difference in life expectancy and mortality?

Observational studies, even though flawed, are the only practical way of coming to a provisional conclusion (and everything in science is provisional).  As I’ve noted many times - we need the data, including the observational outcomes of people committed and following particular diets for the years or decades necessary to determine the long term effects of diet on health and life expectancy.  Not short term studies of months looking at proxies of risk such as blood fat profiles.


Simple. You use the data gathered in the epidemiological studies as observations to form hypotheses.

In this case the hypotheses could be:

Replacing refined grains with whole grains is healthy

Removing all  grains from diet is healthy

Adding whole grains to a grain free diet is unhealthy

Then you test each of these with long term (6 month) RCTs and closely track all risk factors for the specific conditions where correlations were observed.

and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Offline arthwollipot

  • Reef Tank Owner
  • *********
  • Posts: 9146
  • Observer of Phenomena
Re: Any science-based article summarizing a healthy diet?
« Reply #61 on: September 27, 2018, 09:52:27 PM »
I suggest you ask CarbShark and bachfiend for their answers to that question.

Self-described nerd. Pronouns: He/Him.

Tarvek: There's more to being an evil despot than getting cake whenever you want it.
Agatha: If that's what you think, then you're DOING IT WRONG!

Offline jt512

  • Frequent Poster
  • ******
  • Posts: 2616
    • jt512
Re: Any science-based article summarizing a healthy diet?
« Reply #62 on: September 27, 2018, 10:00:40 PM »
These epidemiological studies are observations that show correlations. They are not experiments. They are not the scientific method.

They have validity but by themselves are not sufficient. Their observations of correlations need to be confirmed in RCTs.


CS, they're never experiments.  Get over it.  It is infeasible to run a dietary experiment long enough to detect effects on hard chronic disease endpoints.  The best nutritional data we have come from a combination of epidemiology and basic science.  That is the scientific evidence on which we have to make determinations.  It may be imperfect, but it's the best there is.  If you're not basing scientific judgments on the best available data, then what exactly are you basing them on?  Hunches?  Philosophy?  Religion?  Anecdoctes?  The taste of sourdough bread?
Ich verstehe nur Bahnhof.

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #63 on: September 27, 2018, 10:31:49 PM »
These epidemiological studies are observations that show correlations. They are not experiments. They are not the scientific method.

They have validity but by themselves are not sufficient. Their observations of correlations need to be confirmed in RCTs.

By their very nature, it’s impossible, even in theory, to do RCTs (random controlled trials) with dietary manipulations.  How are you going to be able randomly allocate one group to consuming whole-grain foods and another group to avoiding them, and actually have the groups persist with them for the years or decades necessary to determine if there’s a difference in life expectancy and mortality?

Observational studies, even though flawed, are the only practical way of coming to a provisional conclusion (and everything in science is provisional).  As I’ve noted many times - we need the data, including the observational outcomes of people committed and following particular diets for the years or decades necessary to determine the long term effects of diet on health and life expectancy.  Not short term studies of months looking at proxies of risk such as blood fat profiles.


Simple. You use the data gathered in the epidemiological studies as observations to form hypotheses.

In this case the hypotheses could be:

Replacing refined grains with whole grains is healthy

Removing all  grains from diet is healthy

Adding whole grains to a grain free diet is unhealthy

Then you test each of these with long term (6 month) RCTs and closely track all risk factors for the specific conditions where correlations were observed.

CarbShark,

Six months isn’t ‘long term.’  If you’re trying to determine if consuming whole grains or not is healthy or not, associated with a higher or lower life expectancy or a lower or higher mortality, then you have to do long term studies over many years if not decades.

Short term interventional studies on small populations (which would be the case if you manage to recruit the willing participants) are useless in determining mortality and life expectancy because there’d be so few if any deaths in either group.  ‘Risk factors’ for disease are only proxies for the risk of disease.  If you’re trying to decide whether an intervention has an effect, such as reducing deaths, you have to look at the effect, in this case - deaths.  If you’re looking at proxies, then all you’re demonstrating is that your intervention isn’t obviously immediately lethal.
Gebt ihr ihr ihr Buch zurück?

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #64 on: September 27, 2018, 10:49:07 PM »
I suggest you ask CarbShark and bachfiend for their answers to that question.



I’ve already answered that question.  You’re not paying attention.  My answer was ‘Dietary Guidelines for Americans 2015-20.’  The argument subsequently has deteriorated into one concerning the recommendations of Walter Willett of Harvard University.
Gebt ihr ihr ihr Buch zurück?

Offline jt512

  • Frequent Poster
  • ******
  • Posts: 2616
    • jt512
Re: Any science-based article summarizing a healthy diet?
« Reply #65 on: September 27, 2018, 10:53:53 PM »
I think you’re being a little inconsistent in rejecting the fortification of bread with vitamins on the basis that they’re synthetic, but aren’t willing to criticise Willett for recommending a daily multivitamin tablet.  Where do you think the vitamins in multivitamin tablets come from?


I don't "reject" fortification.  Certainly fortified white bread is better than non-fortified white bread.  I'm saying that whole-grain bread is superior to fortified white bread.  In fact, the more fortified white bread you eat, the more you probably should take a multivitamin, since the multivitamin might contain some nutrient that the fortified white bread does not.

Quote
And anyway.  I need my bread, otherwise I wouldn’t be able to obtain sufficient calories.  As a vegetarian, where am I going to obtain sufficient convenient calories in a food that’s also nutritious?  And don’t be offensive and suggest that i should eat fish.


Um, switching from white bread to whole-grain bread?  Sorry, was it a trick question?  There are also nuts and a plethora of legumes and whole grains, tofu, and olive oil.  I have known a lot of vegetarians, and I have even studied vegetarian nutrition.  You're the only vegetarian I've ever heard of who consumes half his calories from any bread, nevermind white bread.
Ich verstehe nur Bahnhof.

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #66 on: September 27, 2018, 11:23:42 PM »
I think you’re being a little inconsistent in rejecting the fortification of bread with vitamins on the basis that they’re synthetic, but aren’t willing to criticise Willett for recommending a daily multivitamin tablet.  Where do you think the vitamins in multivitamin tablets come from?


I don't "reject" fortification.  Certainly fortified white bread is better than non-fortified white bread.  I'm saying that whole-grain bread is superior to fortified white bread.  In fact, the more fortified white bread you eat, the more you probably should take a multivitamin, since the multivitamin might contain some nutrient that the fortified white bread does not.

Quote
And anyway.  I need my bread, otherwise I wouldn’t be able to obtain sufficient calories.  As a vegetarian, where am I going to obtain sufficient convenient calories in a food that’s also nutritious?  And don’t be offensive and suggest that i should eat fish.


Um, switching from white bread to whole-grain bread?  Sorry, was it a trick question?  There are also nuts and a plethora of legumes and whole grains, tofu, and olive oil.  I have known a lot of vegetarians, and I have even studied vegetarian nutrition.  You're the only vegetarian I've ever heard of who consumes half his calories from any bread, nevermind white bread.

When I was using ‘Carb Manager’ to assess my diet, I found that I was getting all of the RDA of vitamins and minerals from the 9 different vegetables in the vegetable casserole I consume daily, along with the skim milk and skim milk yoghurt, and egg.  Whatever was in the sourdough bread wasn’t actually necessary, but it was quite a lot too.

Sourdough bread is a convenient and readily available source of needed calories.  I’ve tried to get my baker to produce wholemeal sourdough bread, but he’s not interested in doing so.

I also do eat tofu and nuts.  Quite a lot, actually.

As I’ve noted many times - I’m agnostic about diet.  I might be unusual today with consuming half my calories in bread, but I certainly wouldn’t be unusual in past times when bread formed a much larger component of people’s diets because it was cheap, readily available and kept well.  And then people got affluent and became sedentary and adopted diets higher in animal products, and became obese with increasing rates of chronic diseases.
Gebt ihr ihr ihr Buch zurück?

Offline jt512

  • Frequent Poster
  • ******
  • Posts: 2616
    • jt512
Re: Any science-based article summarizing a healthy diet?
« Reply #67 on: September 27, 2018, 11:37:25 PM »
I think you’re being a little inconsistent in rejecting the fortification of bread with vitamins on the basis that they’re synthetic, but aren’t willing to criticise Willett for recommending a daily multivitamin tablet.  Where do you think the vitamins in multivitamin tablets come from?

I don't "reject" fortification.  Certainly fortified white bread is better than non-fortified white bread.  I'm saying that whole-grain bread is superior to fortified white bread.  In fact, the more fortified white bread you eat, the more you probably should take a multivitamin, since the multivitamin might contain some nutrient that the fortified white bread does not.

Quote
And anyway.  I need my bread, otherwise I wouldn’t be able to obtain sufficient calories.  As a vegetarian, where am I going to obtain sufficient convenient calories in a food that’s also nutritious?  And don’t be offensive and suggest that i should eat fish.


Um, switching from white bread to whole-grain bread?  Sorry, was it a trick question?  There are also nuts and a plethora of legumes and whole grains, tofu, and olive oil.  I have known a lot of vegetarians, and I have even studied vegetarian nutrition.  You're the only vegetarian I've ever heard of who consumes half his calories from any bread, nevermind white bread.

When I was using ‘Carb Manager’ to assess my diet, I found that I was getting all of the RDA of vitamins and minerals from the 9 different vegetables in the vegetable casserole I consume daily, along with the skim milk and skim milk yoghurt, and egg.  Whatever was in the sourdough bread wasn’t actually necessary, but it was quite a lot too.

Sourdough bread is a convenient and readily available source of needed calories.  I’ve tried to get my baker to produce wholemeal sourdough bread, but he’s not interested in doing so.

I also do eat tofu and nuts.  Quite a lot, actually.

As I’ve noted many times - I’m agnostic about diet.  I might be unusual today with consuming half my calories in bread, but I certainly wouldn’t be unusual in past times when bread formed a much larger component of people’s diets because it was cheap, readily available and kept well.  And then people got affluent and became sedentary and adopted diets higher in animal products, and became obese with increasing rates of chronic diseases.

I'd be curious if you have any scientific information that any group of humans ever obtained half their calories from bread.  And if any group did, what their health was.

I'm pretty agnostic about the amounts of fats and carbohydrate in the diet, about which there is no scientific consensus.  But not about the quality of carbohydrate and fat in the diet, where there is scientific consensus.  Fats should be mono- and polyunsaturated with an emphasis of n-3 fatty acids.  Carbohydrate should be low-GI and whole-grain. 

You and carbshark have one thing in common: you are consuming extreme diets that the best nutritional evidence says are unhealthy in some major respect: CS eats too much red meat and saturated fat; you eat too much refined carbohydrate. 
« Last Edit: September 27, 2018, 11:46:56 PM by jt512 »
Ich verstehe nur Bahnhof.

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #68 on: September 28, 2018, 12:17:14 AM »
jt,

So?... as I’ve noted many times, I eat bread for its necessary calories.  Bread is a very good calorie rich food.  To get the calories I need and get from 350 g of sourdough bread I’d need to eat kilograms of my vegetable casserole, otherwise I’d be losing weight, which I certainly don’t need to do.

I’d happily compare my physical condition and health against yours any day.
Gebt ihr ihr ihr Buch zurück?

Offline jt512

  • Frequent Poster
  • ******
  • Posts: 2616
    • jt512
Re: Any science-based article summarizing a healthy diet?
« Reply #69 on: September 28, 2018, 12:21:31 AM »
jt,

So?... as I’ve noted many times, I eat bread for its necessary calories.  Bread is a very good [correction by jt512] calorie rich food.  To get the calories I need and get from 350 g of sourdough bread I’d need to eat kilograms of my vegetable casserole, otherwise I’d be losing weight, which I certainly don’t need to do.

I’d happily compare my physical condition and health against yours any day.

In case you are unaware of it, there are other vegetarian foods besides your vegetable casserole and your white bread.
« Last Edit: September 28, 2018, 12:29:53 AM by jt512 »
Ich verstehe nur Bahnhof.

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #70 on: September 28, 2018, 03:22:32 AM »
jt,

So?... as I’ve noted many times, I eat bread for its necessary calories.  Bread is a very good [correction by jt512] calorie rich food.  To get the calories I need and get from 350 g of sourdough bread I’d need to eat kilograms of my vegetable casserole, otherwise I’d be losing weight, which I certainly don’t need to do.

I’d happily compare my physical condition and health against yours any day.

In case you are unaware of it, there are other vegetarian foods besides your vegetable casserole and your white bread.

This discussion is irritating me considerably.

Let’s put it this way - I know my diet is extreme.  Unlike CarbShark I don’t proselytise about it.  I don’t recommend it as the best diet for maintenance of a healthy body weight and good health.  I think that there are wide range of perfectly acceptable diets.

I offer my diet with its 70/12/18 breakdown of C/F/P as a diet at the opposite extreme to CarbShark’s other extreme of less than 5% carbohydrate diet, and I get all the benefits he claims occurs with a ketogenic diet with a low BMI, no hunger, and perfectly normal blood chemistry.

Or to put it another way.  I’m very active physically.  I consume 2800 kcals per day, 1400 kcals coming from bread, and I maintain my body weight of 61 kg and a BMI of slightly over 19 - just.  Any fewer calories, and I’d be losing weight, which I can’t afford to do.  The average diet contains around 2000 kcals a day.  So I’m actually consuming an average vegetarian diet, with all the minerals and vitamins I need, plus an extra 800 kcals from sourdough bread to maintain my body weight.

There aren’t too many foods around that are as calorie rich in such a small volume.  I could eat an extra 8 bananas or apples. Or 10 eggs.  Or what ever combination of vegetarian foods you might suggest, but there’s nothing that comes close to bread in its convenience.
Gebt ihr ihr ihr Buch zurück?

Online CarbShark

  • Poster of Extraordinary Magnitude
  • **********
  • Posts: 11966
Re: Any science-based article summarizing a healthy diet?
« Reply #71 on: September 28, 2018, 10:18:34 AM »
These epidemiological studies are observations that show correlations. They are not experiments. They are not the scientific method.

They have validity but by themselves are not sufficient. Their observations of correlations need to be confirmed in RCTs.


CS, they're never experiments. 
RCTs are not experiments?

Quote
It is infeasible to run a dietary experiment long enough to detect effects on hard chronic disease endpoints. 

Most chronic diseases affected by diet (CVD; TIID; metabolic syndrome, etc.) have well known markers and indicators that can be tracked in RCTs. Further, RCTs of various dietary interventions with extended follow up can track larger changes over time.


Quote
The best nutritional data we have come from a combination of epidemiology and basic science. 

That's flat out false. The large scale epidemiological studies based on Food Frequency questionnaires provide extremely week data, can at best show correlations, and are hampered by numerous weaknesses of the data gathering method (FFQ).

Quote
That is the scientific evidence on which we have to make determinations.  It may be imperfect, but it's the best there is.  If you're not basing scientific judgments on the best available data, then what exactly are you basing them on?  Hunches?  Philosophy?  Religion?  Anecdoctes?  The taste of sourdough bread?

Why ignore the hundreds of RCTs that have been done on diet and nutrition? That is scientific evidence. 
« Last Edit: September 28, 2018, 06:26:49 PM by CarbShark »
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Offline bachfiend

  • Not Any Kind of Moderator
  • Frequent Poster
  • ******
  • Posts: 2080
Re: Any science-based article summarizing a healthy diet?
« Reply #72 on: September 28, 2018, 06:00:16 PM »
CarbShark,

There are no random controlled trials on diet and nutrition.  At best, they’re semi-random (the participants have to know which manipulation they’re being requested to follow, and they have to be motivated to actually follow the manipulation) and semi-controlled (for the same reasons).

In true RCTs, the participants don’t know which treatment they’re receiving, nor do the investigators.  In trials of statins, for example, half of a test group receive the drug being investigated and the other half receive a placebo or another accepted statin, and the two groups are then treated identically.  And at the end of the trial, the results are collated to see if there’s a difference in the results for the two groups.

It’s possible to check for compliance by counting the number of tablets to ensure that the participants are taking the tablets.

None of this applies to trials of diet.  The participants know which diet they’re on.  They’re not treated identically.  If the manipulation is something radical, such as your low carbohydrate/high fat ketogenic diet, then the participants get more counselling, even if it’s only which foods to avoid, and which to eat.  Willett suggested that one of the ways diets work is by making the dieter think about the food eaten.

The ‘markers’ of chronic disease, such as coronary heart disease, type 2 diabetes and metabolic syndrome (which, by the way, were determined by observational studies of large populations) are only proxies of the risk of disease.  Determining whether a dietary manipulation reduces the risk of chronic disease requires determining whether the incidence of chronic disease is reduced.  And the only way of doing that is long term observational studies of large populations.
Gebt ihr ihr ihr Buch zurück?

Offline jt512

  • Frequent Poster
  • ******
  • Posts: 2616
    • jt512
Re: Any science-based article summarizing a healthy diet?
« Reply #73 on: September 28, 2018, 06:17:59 PM »
CarbShark,

There are no random controlled trials on diet and nutrition.  At best, they’re semi-random (the participants have to know which manipulation they’re being requested to follow, and they have to be motivated to actually follow the manipulation) and semi-controlled (for the same reasons).

In true RCTs, the participants don’t know which treatment they’re receiving, nor do the investigators.  In trials of statins, for example, half of a test group receive the drug being investigated and the other half receive a placebo or another accepted statin, and the two groups are then treated identically.  And at the end of the trial, the results are collated to see if there’s a difference in the results for the two groups.

You are conflating two disparate concepts: randomization and blinding.  A trial is randomized when subjects are assigned to treatments via a random process.  Trials may be either randomized or not.  Trials, whether randomized or not, may be single blind, double blind, triple blind, or open label.  In a single-blind trial, subjects do not know what treatment they are receiving; in a double-blind trial, neither do the investigators; in a triple-blind trial, neither do the data analysts.  In an open-label trial, everybody knows everything.

There have been, and there continue to be, lots of dietary randomized controlled trials, some even double blind.  What there have been very few of are long-term diet trials, that is, on a time scale (years to decades) needed to ascertain the effects of diet on hard chronic disease endpoints.  The problem, with such trials, as you have explained, is compliance.  Subjects will not stick to an assigned diet for a decade.  That's why effects of diet on chronic disease have to be ascertained by using a combination of basic science, short-term metabolic trials, and long-term observational studies.
« Last Edit: September 28, 2018, 06:21:15 PM by jt512 »
Ich verstehe nur Bahnhof.

Online CarbShark

  • Poster of Extraordinary Magnitude
  • **********
  • Posts: 11966
Re: Any science-based article summarizing a healthy diet?
« Reply #74 on: September 28, 2018, 06:33:04 PM »
CarbShark,

There are no random controlled trials on diet and nutrition.  At best, they’re semi-random (the participants have to know which manipulation they’re being requested to follow, and they have to be motivated to actually follow the manipulation) and semi-controlled (for the same reasons).

In true RCTs, the participants don’t know which treatment they’re receiving, nor do the investigators.  In trials of statins, for example, half of a test group receive the drug being investigated and the other half receive a placebo or another accepted statin, and the two groups are then treated identically.  And at the end of the trial, the results are collated to see if there’s a difference in the results for the two groups.

You are conflating two disparate concepts: randomization and blinding.  A trial is randomized when subjects are assigned to treatments via a random process.  Trials may be either randomized or not.  Trials, whether randomized or not, may be single blind, double blind, triple blind, or open label.  In a single-blind trial, subjects do not know what treatment they are receiving; in a double-blind trial, neither do the investigators; in a triple-blind trial, neither do the data analysts.  In an open-label trial, everybody knows everything.

There have been, and there continue to be, lots of dietary randomized controlled trials, some even double blind.  What there have been very few of are long-term diet trials, that is, on a time scale (years to decades) needed to ascertain the effects of diet on hard chronic disease endpoints.  The problem, with such trials, as you have explained, is compliance.  Subjects will not stick to an assigned diet for a decade.  That's why effects of diet on chronic disease have to be ascertained by using a combination of basic science, short-term metabolic trials, and long-term observational studies.

At best, long term observational studies will only show correlations, and in part due to the weakness of the methodology (FFQ; few samples for each subject; limited follow up) they are not suited for a complex field like nutrition, and certainly not suited for proving causation between specific foods and chronic diseases.

When they show correlations, there must be followup with further studies (RCTs, etc.) to show any causation. That's not just true for nutrition, but anywhere long-term observational studies are used.
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

 

personate-rain