24 Haziran 2014 Salı

Guest post: Science versus Pseudoscience.

Pseudoscience is so flawed that it cannot be considered legitimate science. Of course it is common to claim that one’s beliefs are scientific, but mostly they are not.

Pseudoscience lacks the true method of science and goes way beyond just a few errors, the methods themselves are so flawed that makes the theory suspicious.

Between the two extremes of science and pseudoscience there is a gray zone, but legitimate science and pseudosciences can still be identified. The denial of this two extremes in the continuum, is a false continuum logical fallacy, or philosophically called the demarcation problem.


Features of Pseudoscience


1. Motivated reasoning


The most prominent feature of this pathological science is working backward from desired results, or motivated reasoning. The result is that they make evidence fit into preconceived notions. They use biased logic and cherry-picked evidence in order to defend a desired conclusion. There’s no concern and effort to prove their own theories wrong.

This relates to the congruence bias, testing one’s own theory by looking for positive evidence and cherry-picked evidence.


2. Burden of proof and confirmation bias


They will only look for confirming evidence, avoid dis-confirming evidence, and may engage in special pleading and shifting the burden of proof.

In confirmation bias, they look for supportive evidence for their own desired conclusions, choosing only the evidence that supports their own theory, irrespective of quality, negative evidence.


3. Anecdotal evidence


Anecdotes are uncontrolled, or ad-hoc observations, and they are not systematic. They rely on confirmation bias and recall bias.

Low-grade evidence is often favored no matter how implausible it may be.

Emotional appeal is another typical tactic among pseudoscientists who try to defend their statements, claiming what people say is more important than actual numbers on paper.

Pseudoscientific belief may even be based upon a single case or observation, preliminary evidence, or even a single anecdote. This is the hasty generalization logical fallacy.

Pseudoscientific principles may also be based upon a philosophical idea, not been empirically tested or developed as a scientific theory.


4. Grandiose claims (Galileo syndrome)


This involves grandiose claims based upon preliminary evidence. Far-reaching claims overturn entire portions of well-established science, using very little research or tiny bits of evidence.


5. Alternative science


In extreme cases, pseudoscience leads to alternative science, all of science is replaced with an alternative version.


6. Absolute claims


Pseudoscientists make bold claims that are often absolute and go way beyond the evidence. Pseudoscientists offer simple answers to complex questions, a theory of everything where one tiny casual source is used to explain the entire universe, if it comes to that.


7. Hostility


Pseudoscientists generally cannot accept criticism and avoid the scientific community. They claim being victim of a conspiracy and stay away from mainstream science and community.


8. Vagueness


Pseudoscientists use vague terms and words to obfuscate, so they can shift the definition around, use it in different ways at different times when it suits them, to confuse others and avoid explaining their point. Vague terms such as “information” or “energy” are often used with no specificity as in a scientific discussion.


9. Stagnation


Pseudosciences fail to progress, and tend to be stagnant. They are ad nauseam trying to establish their theory rather than build a body of evidence for it.


10. Anomaly hunting


Anomaly hunting is yet another common feature in which they search for anomalies trying to establish a conclusion, which does not seek to refute or explore other alternatives.



Nickerson, Raymond. “Confirmation Bias: A Ubiquitous Phenomenon in Many Guises.” Review of General Psychology 2, no. 2 (1998): 175–220.

Novella, Steven. “Anomaly Hunting.” NeuroLogica Blog. http://theness.com/neurologicablog/index.php/anomaly-hunting

Pigliucci, Massimo. Nonsense on Stilts: How to Tell Science from Bunk. Chicago: University of Chicago Press, 2010

Shermer, Michael, The Borderlands of Science: Where Sense Meets Nonsense. New York: Oxford University Press, 2001.

Gardner, Martin. Fads and Fallacies in the Name of Science. Mineola: Dover Publications, 1957
Shermer, Michael. Why People Believe Weird Things. New York: Henry Holt/Times Books, 1997.


For more information on Sérgio Fontinhas, see Big Fitness Project

20 Haziran 2014 Cuma

Another tasty analogy.

Here's a tasty analogy.
From http://grannychoe.com/recipe3_Soup.php

In Ultra-high-fat (~80%) diets: Fat storage, and a delicious analogy, I analogised the effect of carbohydrate consumption on mean serum glucose level with the effect of fat consumption on mean serum triglyceride level. Here's another one.

Chronic excessive consumption of carbohydrates relative to what are being burned results in excessive fat synthesis in the liver, resulting in excessively-high fasting serum triglyceride level, which is harmful.

Chronic excessive consumption of fats relative to what are being burned results in excessive cholesterol synthesis in the liver, resulting in excessively-high fasting VLDL, LDL & IDL level, which is harmful.

Seems legit.

19 Haziran 2014 Perşembe

Siri-Tarino et al, Forests & Trees and "Eureka!" moments.

Here's Fig. 2 from Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease:-
Risk ratios and 95% CIs for fully adjusted random-effects models examining associations between saturated fat intake in relation to coronary heart disease and stroke.

The above "Forest" plot has a subtotal RR of 1.07 (95% CI 0.96 1.19). The overall conclusion is that there's no association between saturated fat intake and the RR for CHD. Hmmm.

I looked at the data in Table 3. Of the 16 studies contributing to the CHD results, only 3 of them specify high sat fat intakes over a wide range. The results from these 3 studies are as follows:-

Pietinen et al: RR=0.93 (95% CI 0.6, 1.44).
Mann et al: RR=2.77 (95% CI 1.25, 6.13).
Boniface et al: Pooled RR = 1.37 (95% CI 1.17, 1.65).

The results from Pietinen et al are statistically-insignificant (95% CI values are way above & below 1) with an overall slight protective effect. The results from Mann et al have a RR >> 1 with both 95% CI's >1 and the results from Boniface et al have a RR >1 with both 95% CI's >1.

Other studies either have sat fat intakes varying from very low to low, or specify mean/median sat fat intakes without values for highest & lowest tertiles/quartiles/quintiles etc. Other studies have results that are statistically-insignificant.

However, there are some studies that show a slight protective effect of small amounts of sat fats. How come?

Thanks to George Henderson, I had a "Eureka!" moment. He posted a link to Dietary intake of saturated fat by food source and incident cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis.

Here's Fig. 1 from that study.
HRs and 95% CI's of CVD risk according to quintiles of energy-adjusted SF from different sources (n = 5209).

The Meat SF plot has a net positive slope (bad news, but the range of intake is very small), the Butter & Plant SF plots are random, but the Dairy SF plot has a net negative slope (good news). Dairy saturated fats in amounts of up to 10g/day are protective against CHD. As the Dairy sat fat intake is too small to have a significant effect on lipids, what's the mechanism? I think that it's Vitamin K2. See Chowdhury et al, More forests & more trees and more "Eureka!" moments with cheese.

When you average out the results from all studies, the result is null. This is data dilution statistics.

EDIT: See also Study: Saturated Fat as Bad as Sugar!

15 Haziran 2014 Pazar

I'm NOT a lipophobe, I'm a very naughty boy!

First, postprandial triglycerides again. From Fasting Compared With Nonfasting Triglycerides and Risk of Cardiovascular Events in Women, here's a plot of HR for future CHD vs TG's at various times after eating.
Hazard ratio (HR) and 95% confidence interval (CI) for highest vs lowest tertiles of triglyceride level (see Table 3 for values), adjusted for age, blood pressure, smoking, hormone use, levels of total and high-density lipoprotein cholesterol, diabetes mellitus, body mass index, and high-sensitivity C-reactive protein level.

Notice how the HR falls with increasing time from last meal. As TG's ≥12 hours after eating are a surrogate for Insulin Resistance (IR) and the HR is only 1.04 (95% CI 0.79 - 1.38), this strongly suggests that IR is not a significant factor.

It's been suggested that IR might increase PP TG's in the 2 - 4 hour period due to impaired clearance. According to Fig. 3B in Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism, TG clearance in healthy men doesn't significantly start until after 4 hours has elapsed. Therefore, an impairment in TG clearance isn't going to make a significant difference to TG level in the 2 - 4 hour period.

Second, the reason why I'm having to repeat myself is due to Cholesterol: Do chylomicrons clog your arteries? (2), where I've been called "my resident lipophobe". As I drink Gold Top milk (5.2g of fat/100mL) and eat pork including belly slices (you know, those strips of pork with a lot of fat on them), I'm being attacked for something that I'm not.

What I'm criticising is dietary extremism. Eating fats in foods is fine by me, but eating sticks of Kerrygold butter and/or dumping loads of butter and/or MCT oil into coffee to achieve "Nutritional Ketosis" is not a good idea. Anyway, here's an amusing spoof on Bulletproof coffee.

12 Haziran 2014 Perşembe

Carbs, Carbs, Carbs, Carbs and Carbs.

Carbohydrates seem to get the blame for everything nowadays. "Carbohydrates made me fat". "Carbohydrates burned-out my pancreas". "Carbohydrates raised my blood glucose". "Carbohydrates raised my blood triglycerides". "Carbohydrates stole mer jerb!". O.K, I made the last one up!
If carbohydrates are responsible for all of these bad things, then how come a diet of only potatoes had the opposite effect? See 20 Potatoes a day.

Also, Blue Zone populations eat a diet with a high percentage of total energy (%E) from carbohydrates. See Low serum insulin in traditional Pacific Islanders--the Kitava Study and The Kitava Study. The Kitavans eat ~70%E from carbohydrates, ~20%E from fats and ~10%E from proteins. They don't eat a significant amount of Western crap-in-a-bag/box/bottle.

Maybe it has something to do with the type of carbohydrates and with what they're eaten. In A very-low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins , (emphasis, mine) "The very-low-fat, high-carbohydrate experimental diet was designed to supply less than 10% of energy from fat (2.7% saturated, 3.7% monounsaturated, and 2.6% polyunsaturated), with 75% from carbohydrate (with equal amounts of naturally occurring and added simple and complex carbohydrate) and 15% from protein." Simple carbohydrates are sugars.

The experimental diet which did bad things contained 37.5%E from sugars. I declare shenanigans!

1. There are simple carbs, there are simple carbs and there are simple carbs. In the previous post, the graph of plasma triglycerides after an OGTT showed that 100g of glucose had no significant effect on plasma triglycerides over a 6 hour period. If it had been 100g of fructose, there would have been a significant increase in plasma triglycerides. Galactose is taken-up by the liver and has minimal effect on blood glucose, but I don't know its effect on plasma triglycerides.

2. There are complex carbs, there are complex carbs and there are complex carbs. Overcooked starch is high in amylopectin which is highly-branched, which means that it hydrolyses rapidly into glucose which gives it a very high glycaemic index. Raw & refrigerated potato starches have very low glycaemic indices, due to the presence of amylose, or other resistant starches. Rice contains a mixture of starches which varies with rice type, cooking time and subsequent refrigeration.

3. There are oligosachharides e.g. FOS.

4. There are polysaccharides e.g. inulin.

5. There is soluble fibre/fiber e.g. cellulose.

Although overeating sugars containing fructose & starches that rapidly hydrolyse into glucose makes the liver fatty, overeating fats also makes the liver fatty. See Pathogenesis of type 2 diabetes: tracing the reverse route from cure to cause.

It's the chronic over-consumption of crap-in-a-bag/box/bottle (high in sugars and/or starches and/or fats), not just carbohydrates, that causes over-fatness and other health problems.

10 Haziran 2014 Salı

Ultra-high-fat (~80%) diets: Fat storage, and a delicious analogy.

Fat storage:

Here's a plot of mean (±SEM) plasma insulin concentrations during an oral-glucose-tolerance test (OGTT) when preceded by either a high-fat (▪) or a high-carbohydrate (□) evening meal and during an oral-fat-tolerance test (OFTT) when also preceded by either a high-fat (•) or a high-carbohydrate (○) evening meal.
From Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

100g of glucose produces a large spike in insulin concentration and 40g of fat produces no significant spike in insulin concentration. According to Gary Taubes' insulin hypothesis of obesity, in the absence of a significant spike in insulin concentration, fat cannot be stored.

Here's a plot of mean (±SEM) plasma triacylglycerol concentrations during an oral-fat-tolerance test (OFTT) when preceded by either a high-fat (•) or a high-carbohydrate (○) evening meal (from the previous post).
From Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism
Average plasma triacylglycerol concentration over 0 to 360min is ~1.3mmol/L (~116mg/dL in US units).

Plasma triacylglycerol concentration falls to baseline between 240min and 360min. OGTT's and OFTT's are performed with the subjects at rest for the duration of the test.

Referring to It's all in a day's work (as measured in Joules) , at rest the subject is burning ~1kcal/min with ~95% of it coming from fat, making a fat-burning rate of ~0.11g/min.

At a fat-burning rate of ~0.11g/min, it would take ~360min for plasma triacylglycerol to fall to baseline if the 40g of fat from the OFTT was only being burned and not being stored. As shown above, it only takes ~120min to fall to baseline. Therefore, fat from the OFTT that isn't burned is stored in ~120min in the absence of a significant insulin spike. Q.E.D.

A delicious analogy:

Here's a plot of mean (±SEM) plasma glucose concentrations during an oral-glucose-tolerance test (OGTT) when preceded by either a high-fat (▪) or a high-carbohydrate (□) evening meal and during an oral-fat-tolerance test (OFTT) when also preceded by either a high-fat (•) or a high-carbohydrate (○) evening meal (from the previous post).
From Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

The OGTT (100g of glucose) produces a large spike in plasma glucose concentration which lasts for ~210min before returning to baseline. Higher plasma glucose concentrations glycate more than lower plasma glucose concentrations. Average plasma glucose concentration over 0 to 360min is higher with the OGTT than with the OFTT, therefore there is more glycation damage with the OGTT than with the OFTT. Don't regularly consume 100g or more of glucose!

Here's a plot of Mean (±SEM) plasma triacylglycerol concentrations during an oral-glucose-tolerance test (OGTT) when preceded by either a high-fat (▪) or a high-carbohydrate (□) evening meal.
From Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism
Average plasma triacylglycerol concentration over 0 to 360min is ~1.0mmol/L (~89mg/dL in US units).

Although the plasma triacylglycerol concentration after consuming a high-carbohydrate evening meal is slightly higher than after consuming a high-fat evening meal, the two plots above are essentially flat, indicating that none of the 100g of glucose consumed was turned into fat by de novo lipogenesis (DNL) within 6 hours.

As discussed in the previous post, higher plasma triacylglycerol concentrations are more atherogenic than lower plasma triacylglycerol concentrations. Average plasma triacylglycerol concentration over 0 to 360min is higher with the OFTT than with the OGTT, therefore there is more atherogenicity with the OFTT than with the OGTT.
Don't regularly consume 40g or more of fat!

An interesting study that involved humongous fat consumption was Response of body weight to a low carbohydrate, high fat diet in normal and obese subjects , which used up to 600g of fat/day. It's possible to lose weight on an ultra-high-fat diet, but average plasma triacylglycerol concentrations would have been extremely high. Fasting TG's reduce on an ultra-high-fat diet, probably due to suppression of endogenous TG synthesis by exogenous TG intake.