I have a theory.

I was keeping this theory a bit quiet 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 in any way, shape or form. I'm just trying to point out that if someone on a low-carb, high-fat diet pigs-out on roast lamb/pork/duck etc, they may not lose as much body fat as they expected & they may even gain some.

I don't particularly want to start a sh*t-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 & 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.

As a lot of people report that they appear to be able to eat lots of dietary fat without getting fat (& actually getting slim), there's obviously something magical going on. Now, it's generally accepted that fat is the least thermogenic of all the macronutrients (protein being the most thermogenic). I'm wondering whether this is the case for all types of fat and all types of people.

Stephan Guyenet blogged on Butyric Acid: an Ancient Controller of Metabolism, Inflammation and Stress Resistance and Coconut Oil (high in medium chain fats) is also reported as being less fattening/more slimming than long-chain fats.

As Christopher Gardner said 39m 34s into his lecture Battle of the Weight Loss Diets: Who's Winning (at losing), insulin resistant people do better on high-fat, low-carb (HFLC) diets than high-carb, low-fat diets. Insulin sensitive people are the other way round.

So it's quite possible that in people who do well on a HFLC diet, kcals out on the right hand side of the Energy Balance Equation increase a lot. So, keep on keeping on!

See also:-
More evidence comes to light that fat is not fattening
Is there such as thing as a ‘metabolic advantage’?
They're all MAD!
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 and Enzymes.

I've got a lovely bunch of coconuts!

Coconut Oil is the No. 1 most stable oil for cooking at high temperatures.

What’s in coconut oil?

According to http://www.manitobaharvest.com/nutrition/index.asp?itemID=183 , coconut oil is ~91% saturated fatty acids, ~7% monounsaturated fatty acids, ~2% omega-6 fatty acids and zero omega-3 fatty acids.

According to McCance and Widdowson's “The Composition of Foods”, the fatty acid composition of coconut oil is as follows:-

Name(:0=sat, :1=mono, :2=poly, n6=omega-6) Quantity (%)
Caprylic Acid (C8:0)___________________________7.5
Capric Acid (C10:0)____________________________7.1
Lauric Acid (C12:0)___________________________47.7
Myristic Acid (C14:0)_________________________15.8
Palmitic Acid (C16:0)__________________________9.0
Stearic Acid (C18:0)___________________________2.4
Arachidic Acid (C20:0)_________________________1.0
Palmitoleic Acid (C16:1)_______________________0.4
Oleic Acid (C18:1)_____________________________6.6
Linoleic Acid (C18:2 n6)_______________________1.8

Won’t all that saturated fat give me a heart attack?

Whether or not you get coronary heart disease depends on your whole diet. According to http://www.ajcn.org/cgi/reprint/34/8/1552.pdf , Pukapukans got 26% (male) to 30% (female) of their total Calories from saturated fats. Tokelauans got 47% (male) to 49% (female) of their total Calories from saturated fats. Tokelauans had total serum cholesterol 35-40mg/dL (0.9- 1.03mmol/L) higher than Pukapukans.

As Tokelauans were getting about seven times more energy from saturated fats than the 7% that current healthy eating guidelines recommend, they must have been dropping like flies from coronary heart disease or strokes, right? Wrong! To quote:-
“Vascular disease is uncommon is both populations and there is no evidence of the high saturated fat intake having a harmful effect in these populations.”
How come? Well, if you look at the rest of the Tokelauans’ diet, you’ll see virtually no refined sugar or cereal products. Basically, they weren’t eating any junk. When Tokelauans migrated to New Zealand, their sat fat intake fell to ~41% of total calories but as they were eating more refined carbs & sugar, their lipid profile got worse.

What are the benefits of coconut oil?

Medium-chain fatty acids are metabolised rapidly without passing through the liver and they provide a quick source of energy for muscles. There is some evidence that medium-chain fatty acids stimulate the thyroid gland to secrete more T4 & T3 which can be an aid when cutting. There is also some evidence that Lauric Acid has anti-bacterial & anti-viral properties. Coconut oil is also good for the skin when rubbed in.

Where can I buy coconut oil?

Don’t buy cheap coconut oil. It’s almost certainly Refined, Bleached & Deodorised which detracts from its health benefits. The best coconut oils are Organic Virgin Oils. Some good on-line sources are
http://www.fresh-coconut.com/ ,
Coconut Oil UK and
http://www.revital.co.uk/product_search.cfm?searchString="Nutiva+Organic+Extra+Virgin+Coconut+Oil"

In addition, check-out Rosso's Blog on Saturated oils.