After last week's post on the American Diabetic Association's change in their food recommendations, I got an email from my cousin who told me that I had the physiology of diabetes wrong - that it is not impaired sugar metabolism that is the problem, but rather impaired fat metabolism. My cousin has a PhD in biochemistry and his thesis was on metabolism, so if he tells me I've got something wrong, I've probably got it wrong. He sent me a couple of review papers to back up his position, one published as early as 2001, and I find it amazing that I never caught a whiff of this concept before, despite actively researching all the time. My goal is to be accurate, not to be right, so I am very grateful to my cousin for teaching me something new.
So, what these papers have shown is that when fat metabolism goes wrong, free fatty acids are deposited in muscle, liver or pancreatic tissue instead of fat cells, which degrades the function of the insulin receptors in those tissues, basically closing the door to insulin and therefore glucose, leaving them in the bloodstream. So high blood glucose and high insulin levels are a RESULT of insulin resistance, rather than the cause of it as I was previously suggesting, and insulin resistance appears to be caused by too many fatty acids. So, does that mean that we should be eating low-fat diets in order to reduce the free fatty acids and triglycerides in the bloodstream? Is the low-carb thing completely wrong?
I think it depends. A sports car needs a high octane fuel for maximum power. The engine of a transport truck would probably be ruined on such a fuel - it needs a diesel fuel to run efficiently. Just as you would not use the same kind of fuel mix in a transport truck as you would in a sports car, it is illogical in my opinion, to assume that every human being's metabolic engine needs exactly the same fuel mix. McGarry in his article discusses the notion that some people burn (oxidize) fat sub-optimally, and that seems to lead to insulin resistance. In the metabolic-typing world, we call these people slow oxidizers, and because their metabolic engine runs slowly, they need to eat a diet that is low in fat. They need to eat more carbohydrate for optimum performance.
In my experience as a metabolic typing advisor, I've noticed that among the people I've tested in my area, there are far more fast oxidizers than slow oxidizers. These people are like the sports car - their engines burn too fast, and the fuel mix that slows down their metabolic engine is a diet low in carbs, (especially starch and sugar) and higher in fat and protein. And if these people eat more carbs than the body can use for energy, those carbs get converted to fat. We are supposed to keep producing fat cells in order to store what we don't use, but some people don't (lipodystrophy), so in those people the fatty acids may then get deposited inappropriately in the muscles and liver causing insulin resistance as discussed above. So maybe high fat diets are a problem for some, and high carb diets are a problem for others, depending on the metabolism of the individual. This is conjecture on my part, but to me it makes sense that if we provide for our bodies a clean, high-quality fuel mixture that is appropriate for our own metabolic engines, then the fuel will burn cleanly, efficiently, and will not throw off substrates like ceramides that mess us up. Maybe Type 2 Diabetes is a disease of eating the wrong food ratios (fuel mix) for one's metabolic engine. If this is the case, it becomes obvious that there will never be one food plan that will work for everyone. The diet suggested must match the metabolism of the individual. In my experience, those that actually eat according to their metabolic type resolve their metabolic issues.
Type 2 Diabetes was only recognized as a rare separate form of diabetes in 1959, is a now a disease that is growing in prevalence at a staggering rate. A child born in 2000 stands a one in three chance of being diagnosed with diabetes in his/her lifetime. Science is trying to solve the problem by looking through a microscope, but I think that it is more useful to back up and look at the big picture. Evolutionarily speaking our bodies have not changed since the time when Type 2 Diabetes was rare, but our lifestyles have changed radically. Our ancestors were born, lived and died in the same region, generation after generation. We can live anywhere in the world. Our gene pools have mixed. Our food habits have completely been turned on their head - we are eating flour and sugar like never before in our evolutionary history, and we have access to pretty much any kind of food in the world. The Inuit who need a fuel mix that is high in saturated fat and protein to be healthy are now suffering rampant Type 2 Diabetes because they are now eating more carbohydrate that is suddenly available to them. We are eating vegetable oils, which didn't exist before 1900. We are eating processed foods filled with chemical flavourings, preservatives, colourings etc. Physical activity is no longer needed for survival. We are staying up late with the help of artificial lights, which raises our blood sugar. To me it makes sense that to stop Type 2 Diabetes, we need to stop eating food that comes from a factory and instead choose high quality real food that comes from a farm or from the wilderness. Since flour and sugar are in processed food, we should avoid them just as we should avoid fast food, which tends to be made from poor quality fats. We can make exercise a part of our daily life, and we can get to bed early so we have enough hours in the dark.
I look forward to your comments on my blog. If you want me to metabolically type you, reply to this email.
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Holland WL et al. Inhibition of ceramide synthesis ameliorates glucocorticoid-, saturated-fat-, and obesity-induced insulin resistance. Cell Metab. 2007 Mar;5(3): 167-79.
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Copyright 2008 Vreni Gurd
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