Right now my friend I will put you on the spot, can you explain the reasons for improved lipid panels that we see so often reported by lowcarbers. This question has been raised many times but so far no one has been able to answer. My interpretation is that it's the carbs having a negative effect on cholesterol levels rather than the fats, if you can come up with a different theory I'd love to hear it
Sorry everybody...he did ask and if I didn't answer I'd have to keep reading that no-one ever gives an answer :!:
Well believe it or not, I partly agree but I think much is to to with what you have changed from ie the type of carbs, and in what form they are eaten
Any answer will have to be speculative , and I'm not making any claims for it's veracity.
1)
There are people who do not find this improvement on a low carb diet. I have noticed this on forums but its also clear from the studies.
In the Yancy 2002 study 29 out of the 41 who completed the study showed an improvement in their lipid panels, however the remaining subjects levels rose. (one saw their LDL rise from 123mg/dl to 225mg/dl) There were also 10 subjects who gave up the diet and the researchers say that tthese subjects may or may not have had adverse effects.(they don't know)
In the 2004 study, the low carb group had a better overall reduction in lipid profiles
but 2 subject's dropped out because of increased cholesterol levels (In one LDL rose by 100mg/dl in four months ) Among participants for whom data on LDL cholesterol were available at both baseline and week 24, the LDL cholesterol level increased by more than 10% in 13 (30%) of 44 recipients of the low-carbohydrate diet compared with 5 (16%) of 31 recipients of the low-fatdiet (P 0.2). Oh and one of the low carb subjects dropped out because he ended up in hospital with CVD. (in spite of his cholesterol levels decreasing). In the discussion the writers also say and I quote it because it is a reminder that one size does not fit all
Our results confirm the decrease in serum triglyceride level seen in previous studies (5–10, 15, 25, 26). Our data are limited, however, to persons with normal or moderately elevated baseline triglyceride levels. Persons with fasting chylomicronemia (serum triglyceride level > 5.64 mmol/L
[>500 mg/dL] and usually > 11.3 mmol/L [1000 mg/dL]) may have fat-induced lipemia, meaning that high fat intake further increases serum triglyceride levels. In these persons, a low-fat diet is the standard of care for decreasing triglyceride levels and therefore preventing pancreatitis
Weight loss will have played an important part in before and after lipid profiles. The primary dyslipidemia related to obesity is characterized by increased triglycerides, decreased HDL levels, and abnormal LDL composition. Loose the weight and levels normalise.
2) So why do some improve?
I often read a friend of yours claiming that he is now eating more healthily than ever, If this is typical, then it is possible that the new diet contains more of those things that improve the lipid profile than previously . Giving up energy dense, low nutrient foods and replacing them with beneficial fats will result in a healthier diet than before. The resulting diet maybe lower in sat fat than before.( Have you read some of the labels on highly processed ready meals , pizzas, sausage rolls, crisps pasties and pies, just cutting out a few may result in a huge reduction of intake of both refined carbohydrates and saturated fats)
One obvious answer is an increased intake of omega 3s fatty acids (linseed,nuts fish etct)
Mendosas diet which I noted earlier is full of these efas which increase the fluidity of the blood causing blood to flow through the vessels more easily. It will quite probably increase HDL and reduce trigs. All that flaxseed in faux bread mixes and snacking on macedemia nuts must help, as must the increase in fibre for those who previously hated veg. (but like all things can be overdone, as the results of Hugh Sinclairs self imposed Inuit diet showed, just google it!)
Perhaps some of those whose lipids increase take the injunction to eat lashings of cream, butter and cheese more literally than others(?)
3) Are the very large rises that a few individuals find in HDL beneficial ? (and this is hugely speculative, my own HDL levels are slightly above the range for a woman of my age )
One author suggests that very high levels of HDL on high fat diet are because the HDL is means of eliminating the plaque from the blood vessels. People with abnormally high HDl levels need them because they have high levels of lipids to dispose of. There is also some evidence that at least in some cases very high hdl levels are not protective.(see
http://www.lipidsonline.org/news/article.cfm?aid=5936
Finally, I could ask the same question back of you? Why do people who reduce their sat fat and eat more whole grains, fibre fruit and veg show improvements in lipid profiles. Barnard's vegan study for example shows a huge improvement in lipids and this diet was very high carb and no animal fat .
Maybe you could also explain the part that carbs play in the rise in obsesity, cvd etc when carbohydrate intake has fallen from providing 66% of energy in 1880 to 47% in 2003 (only a drop of 1% since 1962, added sugar has also fallen from a postwar high to 6%, less than in the 1880s.)
I have a theory that many problems stem from the introduction of a certain make of crisps in the 60s... A portable high fat/high carb snack .
Actually as you know we could go on debating for ever so for the sake of everyone else you could treat those as rhetorical questions!
