I'm not quite sure what the picture below means (I need to do a spot of reading!).
Metabolic flexibility "bowl" and "Adaptability envelope"
While replying to Kade Storm this morning, it suddenly occurred to me that the Eskimos have an unusual ability. RER (a.k.a. RQ) normally varies from 0.7 (100% fat-burning) to 1.0 (100% carb-burning aerobically) to >1.0 (100% carb-burning, some anaerobically). Eskimos manage to get an RER of 0.600 *Mind blown.*
One theory that comes to mind is BAT. As Eskimos live in a very cold environment, it's possible that this has resulted in them having a large amount of BAT. BAT is very metabolically-active and turns ATP into heat via UCPs.
Nowadays, first-world people don't live in a cold environment (unless they're old and/or poor), so we don't have much BAT after infancy. Naturally-skinny people may be that way due to having more BAT. They seem to be able to eat whatever and as much as they want without getting fat. I'd like to scratch their eyes out! ;-)
Before I start on what may be the most important thing that I've ever written, here's Don't Stop Movin' by S Club 7. It's a clue to what's coming.
The problem:
Insulin Resistance (IR) is a major problem for a significant percentage of the population in the developed world. If left untreated, it can deteriorate into Type 2 Diabetes (T2D). See Type 2 diabetes in the UK.
IR & T2D can cause:-
High fasting & postprandial serum glucose, which increases the risk factor for Coronary Heart Disease, Retinopathy, Neuropathy& Nephropathy (Kidney failure), amongst other things. High fasting & postprandial serum triglycerides, which increases the risk factor for Coronary Heart Disease. See Lifestyle Intervention Leading to Moderate Weight Loss Normalizes Postprandial Triacylglycerolemia Despite Persisting Obesity. High serum cholesterol, which increases the risk factor for Coronary Heart Disease. High serum Free Fatty Acids (a.k.a. FFAs a.k.a. NEFAs) from IR fat cells, which increases the risk factor for Sudden cardiac death and also worsens IR in liver & muscle cells. High serum uric acid, which increases the risk factor for Gout & Uric acid Kidney stones. Hypertension, which raises the risk factor for Coronary Heart Disease, Strokes & Kidney failure. Excessive appetite after eating high-GL carbohydrates, leading to overeating & obesity. Lethargy/sleepiness after eating almost anything, but especially after eating high-GL carbohydrates, due to postprandial hyperinsulinaemia.
Possible causes (IR is multi-factorial) and solutions:
1."Bad" genes. My genes aren't particularly good, but it is possible to change the expression of genes. See below.
2.Full cells. A full cell is an IR cell. Consider Liver, Muscle and Fat cells:-
a) Liver cells: Liver cells are a 2-way street. "Stuff" (e.g. FFAs, Glucose & Fructose) goes in and "stuff" (e.g. Ketones & Glucose) comes out. Glucose normally comes out of the liver at a rate of ~5g/hour to fuel the brain, but this can increase a lot under the control of Insulin, Glucagon & Cortisol. If more stuff goes in than comes out, liver glycogen stores fill up and vice-versa. When liver glycogen stores become full, liver cells down-regulate processes that produce liver glycogen e.g. hexokinase & Glu-T2 transporters. Liver cells effectively become IR, to stop more stuff from going in.
However, fructose is transported by Glu-T5 transporters which are insulin-independent & taken up by fructokinase which has a high affinity for fructose, so fructose effectively "barges its way in" to the liver. This is why fructose is a problem for people who have permanently full liver glycogen stores.
b) Muscle cells: Muscle cells are a 1-way street as far as Glucose is concerned, though Amino Acids can go in & come out. Muscle glycogen cannot be used to produce blood glucose - it can only be used by muscles. When muscle glycogen stores become full, muscle cells down-regulate processes that produce muscle glycogen e.g. hexokinase & Glu-T4 transporters. Muscle cells effectively become IR to stop more stuff from going in.
As per It's all in a day's work (as measured in Joules), muscle cells use mostly fat at rest & lowish-intensity exercise. Glycogen usage increases rapidly as exercise intensity increases. Now do you see the significance of the music video above? Intense exercise (e.g. Running, Sprinting, Resistance training with weights, parts of High-Intensity Interval Training a.k.a. HIIT, parts of Tabata & parts of Zumba) depletes your muscle cells and makes them Insulin Sensitive.
c) Fat cells: Fat cells are a 2-way street. Fat cells are a bit like balloons that are full of holes. As stuff (e.g. FFAs & glucose) goes in, the balloon expands to accommodate it. As more stuff goes in and the balloon gets bigger, the internal pressure increases and the holes get bigger, so stuff (e.g. FFAs & glycerol) comes out at a faster rate. At some level of fullness, stuff comes out as fast as it goes in. At that point, fat cells are effectively IR. So, don't overstuff your fat cells by getting too fat. If you are already too fat, medium intensity exercise (e.g. Walking, Power Walking, Jogging, "Aerobics", parts of High-Intensity Interval Training a.k.a. HIIT, parts of Tabata & parts of Zumba) depletes your fat cells and makes them Insulin Sensitive.
3. Empty (of glycogen) cells.
If carbohydrate intake is too low (say, less than 50g/day), physiological Insulin Resistance develops in order to spare glucose for the brain (as parts of the brain run on glucose only) and red blood cells. This is reversible on increasing carbohydrate intake. People who are on ketogenic diets are advised to increase their carbohydrate intake for a few days prior to taking an Oral Glucose Tolerance Test. See HIGH CARBOHYDRATE DIETS AND INSULIN EFFICIENCY.
In January 2003, I had Impaired Glucose Tolerance/Metabolic Syndrome/Prediabetes (fasting serum glucose = 5.8mmol/L & 2 hours post-75g glucose load serum glucose = 8.7mmol/L). A sandwich used to send me to sleep.
By September 2008, I had Normal Glucose Tolerance (fasting serum glucose
= 5.0mmol/L & 2 hours post-75g glucose load serum glucose =
3.7mmol/L). I also no longer suffered from carbohydrate-induced comas. I was also about the same weight that I was in 2003, so the improvement wasn't due to weight loss. Hypovitaminosis D was the primary contributor to my IR.
So, either use a UVB sun-lamp as per instructions to receive a sub-erythemal dose (not quite going pink) or get tested by your GP and supplement with Vitamin D3 accordingly. I take 5,000iu of Vitamin D3/day.
5.Deficiency in Magnesium.
See Magnesium and type 2 diabetes. For the top 999 foods highest in Magnesium per 200kcal serving, see HERE. I've been taking ~4g of Epsom Salts/day (~400mg Mg/day, dissolved in 2 litres of fluids that I drink each day, to avoid laxative effects) since 2003 as it reversed osteoporosis in my lumbar spine.
10.Excessive intake of man-made trans-fats.
Base your diet on minimally refined produce rather than over-refined &/or moreish food products.
11.Excessive intake of chemicals.
Don't swallow toothpaste (fluoride) or disclosing tablets (as they may contain iodine). Don't hold till receipts between your lips (may be coated in BPA).
Finally, the obligatory picture. Hannah Spearritt is rather nice. :-p
I nearly forgot! Today, when I arrived at mum's nursing home, I found her reading a book. She hasn't done that for over a year. She even knew that it was Wednesday. Ketogenic diet for the win. Mum now has a dual-fuel brain. EDIT: Mum passed away in April 2013, so although it's possible to slow the progression of Lewy Body Dementia and reduce the symptoms of it, it wasn't possible to cure it.