Public Service Announcement: Calling all Low-carb, Low-fat and Veg*n advocates.

Cont'd from The cause of America's rising obesity rate is irrelevant. The cure for it is what's important.

While you're arguing about which arrangement of deckchairs on deck is best, the ship is sinking.

From https://twitter.com/MaxCRoser/status/936695363167313920

People are getting fatter and sicker in increasing numbers around the world, due to increasing numbers of people over-consuming over-refined, over-marketed & over-moreish Food Products. Getting people to change their diet back to one based on minimally-refined produce would be an improvement.

Why don't you agree to say the same thing, e.g.:-

Base your diet on whole, minimally-refined produce, rather than products. Tweak it to suit.

While you're wasting time shouting each other down, the Food Product Industry is laughing all the way to the bank.

Cont'd on Free will? It's just an illusion! How the Food Product Industry gets people to dance to their tune, part 1.

When bad science goes...pretty much the same!

After the previous post, you may have got the impression that things are getting worse. Hmmm!

From http://covermyfb.com/covers/27316/say%2Csee+and+hear+no+evil

Hat-tip to James Beckerman, MD for https://twitter.com/jamesbeckerman/status/507544419847786496, which refers to Comparison of Named Diet Programs Finds Little Difference in Weight Loss Outcomes.

This study comes to the opposite conclusion of the study in my previous blog post. As that study was a pile of poo, that must mean that this study is 100% correct, right? Hmmm!

Your enemy's enemy is not necessarily your friend. See What about the Other Weight Loss Diet Study??
"Previous meta-analyses, such as Hession et al, had balanced inclusion criteria that allow us to directly compare low-fat to low-carb diets.  They reported exactly what anyone would expect who is familiar with the weight loss diet literature:

1. At 6 months, low-carb diets consistently lead to greater weight loss than low-fat diets. 
2. At one year, the difference has all but disappeared. 
3. Neither diet produces particularly impressive weight loss at one year or more.
4. The weight loss effectiveness of typical low-fat diets tends to be modest at all time points.

Oh, well. It could have been a lot worse!
 

When good science goes bad, part n+1.

In When good science goes bad , I looked at the effect of funding bias on research.

From https://www.youtube.com/watch?v=sJ5jbxMjexo

Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial has just been published. As expected, low-carbers are positively creaming themselves over it. I instantly smelled a rat, as the full study was behind a pay-wall.

Remembering Krauss' shenanigans with "carbohydrate", consisting of 50% sugars + 50% "complex" carbs (maltodextrin & amylopectin are complex carbs that hydrolyse into glucose so rapidly that they have a GI of 100 on the "Glucose=100" scale.), I suspected dodgy carbs in the "Low-fat" group.

Luckily, David L. Katz, MD, MPH, FACPM, FACP had read the full study, and wrote about it in Diet Research, Stuck in the Stone Age.

As I suspected, it was another "fix-up" job, rigged to make low-carb diets look good, and low-fat diets look bad.

See also:-
Low-carbohydrate vs. Low-fat diets for Weight Loss: New Evidence,
What I Learned By Actually Reading That Low-Carb Is Best Study,
Is low-carb really the best weight loss diet? and
A Question about the latest diet study ...

How low & very low-carbohydrate diets don't work.

Having explained how low & very low-carbohydrate diets work, here are a few ways in which they don't work.

Uh, nope!

1. Hormonal clogs: This is a term used by Jonathan Bailor. I don't think he's referring to wooden shoes! The "clog", I'm guessing, is supposedly caused by that dastardly hormone insulin. Uh, nope!

See the following plots of RER vs exercise intensity after being on high-fat diet or low-fat diet.

RER = 0.7 ≡ 100%E from fat. RER ≥ 1.0 ≡ 100%E from carb.

The low-fat diet results in higher RER, so the body is burning a higher %E from carb and a lower %E from fat.

However, this doesn't make any difference to weight loss, as it's merely a substrate utilisation issue. In addition, when the body is burning a higher %E from carb, this depletes muscle glycogen stores faster, which lowers RER during the course of the exercise. So, it's not a problem.


2. Insulin: This is Gary Taubes' hypothesis. Insulin makes your body store carbohydrates as body fat. Uh, nope!

The only time that there's significant hepatic DNL is when there's chronic carbohydrate over-feeding. If you eat sensibly, there's no significant hepatic DNL.


3. A Calorie isn't a Calorie, where weight change is concerned: This is Richard D Feinman's hypothesis. "A calorie is a calorie" violates the second law of thermodynamics, therefore there's a metabolic advantage with low-carbohydrate diets. Uh, nope!

Where to start? Evelyn Kocur knows her Physics, so I'll start there. See The first law of thermodynamics (Part 1) and The first law of thermodynamics (Part 2).

From Second Law of Thermodynamics:-
"Living organisms are often mistakenly believed to defy the Second Law because they are able to increase their level of organization. To correct this misinterpretation, one must refer simply to the definition of systems and boundaries. A living organism is an open system, able to exchange both matter and energy with its environment."

People on ketogenic diets excrete very few kcals as ketone bodies. See STUDIES IN KETONE BODY EXCRETION (PDF). There is no significant Metabolic Advantage with low-carbohydrate diets.

Low-glycaemic diet seen to reverse diastolic dysfunction of diabetes.

From http://www.medscape.com/viewarticle/802947?nlid=30763_1301&src=wnl_edit_dail (Medscape log-in required):-

"Of 32 overweight or obese diabetic patients (mean body-mass index, 34) without cardiac disease who were engaged in a "rehabilitation program in order to lose weight" that included two hours of supervised aerobic exercise per day, half followed a low-glycemic diet (25% carbohydrate, 45% fat, 30% protein) and the other half a low-fat diet (55% carbohydrate, 25% fat, and 20% protein) for three weeks. The diets provided the same amount of calories. Those on the low-fat diet then switched to the low-glycemic diet for an additional two weeks"

"....the two diets led to about the same declines in weight and waist circumference..."

The diet was 25% carbohydrate, 45% fat, 30% protein.
It was a low-carbohydrate/low-glycaemic load diet.
It was not a very-low-carb diet.

We are not all the same.

Cont'd from Everyone is Different.

Lyle (McDonald) brought the following study to my attention to illustrate that "We are not all the same":- Some Metabolic Changes Induced by Low Carbohydrate Diets. On a very-low-carb diet, one subject’s total cholesterol rose to 12.9mmol/L (500mg/dL in US units). The others didn't.
See also LDL cholesterol goes sky high on fatty diet.

I posted the study in various blogs to make the above point. Here are some of the replies I got:-
"Lyle? Lyle McDonald? Is that where you got that study, Nigel?" and... "I’m usually a pretty polite guy, Nigel. But based on this quote from the beginning of the study you mentioned, the people who wrote this study were a bunch of f**kwads, and really don’t deserve our attention. It’s a hatchet job."
"That was a weird study (1967) what I could make of it." and... "The men did all the stages but the women only did 3 stages of the diet."
"The fats were mostly omega-6 PUFA 13-35 grams worth..."
"The report you cite is so old and out of date that it makes me cry..."

My point was well & truly missed. I got the distinct impression that people thought I was criticising very-low-carb, high-fat diets. I wasn't. The simple fact is that there is no "One True Diet" that suits absolutely everybody. In the olden days everywhere & in poor countries nowadays, people that ate/eat the wrong diet for their body died/die young. Nowadays in rich countries, they get put on drugs e.g. oral hypoglycaemics (to lower blood glucose) & hypolipidaemics (to lower blood cholesterol/triglycerides).

Please note that omega-6 PUFAs tend to lower serum cholesterol rather than raise it, as per Figure. 1 below from Individual fatty acid effects on plasma lipids and lipoproteins: human studies.

However, don't rush off and eat shed-loads of omega-6 PUFA (e.g. corn oil) in the mistaken belief that it will make you live any longer.

Cont'd on Everyone is Different, Part 2.

I have a hypothesis.

I was keeping quiet about this, as it contradicts Gary Taubes, Michael R Eades & Richard D Feinman and Eugene J Fine.

Please note: This post is not criticising low-carb, high-fat diets. I'm pointing out that if someone on a low-carb, high-fat diet exercises as much gluttony as they want on roast lamb/pork/duck etc, they may not lose as much weight/body fat as they expected & they may even gain.

I don't want to start a shit-storm, but as I am in the "a calorie is a calorie" (when it comes to weight gain/loss) camp and a lot of the people whose blogs I link to aren't, I need to go public. So, here it is, copied and pasted from the comments section of Diet, Carbs, Fat and Weight Loss, corrected for spelling.

"I would like to propose a theory which explains how fat cells can acquire glucose (& thus correct a deficiency in glycerol-3-phosphate) even when serum insulin level is basal.

Consider muscle cells undergoing anaerobic activity:-

Anaerobic activity is very inefficient and uses pyruvate at a very rapid rate. A deficiency in pyruvate up-regulates all of the up-stream processes, including Glu-T4 transporters so as to maximise pyruvate production.

This explains why resistance training with weights greatly increases muscular insulin sensitivity and why resistance training with weights when depleted of muscle glycogen can cause precipitous drops in blood glucose level.

Ditto for glycerol-3-phosphate in fat cells. In this case, blood glucose level is maintained by the liver & kidneys, which convert the glycerol backbone of triacylglycerols (fats) and other substrates such as lactate, pyruvate & glucogenic amino acids into glucose."

In plain terms what this means is that, like muscle cells, fat cells can acquire as much glucose as they need, independently of carbohydrate intake.

Therefore, if an excess (beyond what the body is burning) of dietary fat is eaten, this can be stored in fat cells even if serum insulin level does not increase.

There. I've said it. I expect comments. Moderation is enabled. All comments that are free from ad-hominem, straw men & other logical fallacies will be published.

EDIT: Here's evidence that dietary fat can be stored in the absence of dietary carbohydrate. It involves doing maths on an Oral Fat Tolerance Test:- On burning, storing and recomposing.

EDIT: Here's evidence that a calorie is a calorie (where weight change is concerned):- Bray et al shows that a calorie *is* a calorie (where weight change is concerned).
 
As a lot of people report that they can eat dietary fat without getting fat (& actually getting lighter & slimmer), there appears to be something "magical" going on. It's generally accepted that fat is the least thermogenic of all the macronutrients & protein is the most thermogenic. I wonder if this is the case for all types of fat and all types of people.

See Butyric Acid: an Ancient Controller of Metabolism, Inflammation and Stress Resistance.

From Battle of the Weight Loss Diets: Who's Winning (at losing):-
Insulin Resistant people lose more weight on low-carb, high-fat (LCHF) diets than high-carb, low-fat (HCLF) diets.  
Insulin Sensitive people lose more weight on high-carb, low-fat (HCLF) diets than low-carb, high-fat (LCHF) diets.

According to Gary Taubes's Carbohydrate Insulin Hypothesis, everyone should lose more weight on low-carb, high-fat (LCHF) diets than on high-carb, low-fat (HCLF) diets. Therefore, Gary Taubes's Carbohydrate Insulin Hypothesis is false.

It's possible that in people who do well on LCHF diets, kcals out on the right hand side of the Energy Balance Equation increase significantly. So keep on keeping on.

EDIT: With the benefit of four more years of knowledge, here's why LCHF & ketogenic diets have an advantage for people who have Insulin Resistance. How low-carbohydrate diets result in more weight loss than high-carbohydrate diets for people with Insulin Resistance or Type 2 Diabetes.

See also:-
Metabolic Advantage of Ketogenic Diets Debunked? An Intriguing Study You Will Want to Read
Is the Fable of Unfettered Fat Burning Derailing Your Low Carb Diet?

See also How stuff works & Enzymes.