Interesting article.  I would definitely support the "Long term ketogenic diets can lead to problems where the body thinks its starving and down-regulates thyroid function" statement

However, I do think that a 20% carbs, 65% fat, 15% protein ratio would be rather difficult to achieve unless one eats a *lot* of bone marrow!  20/55/25 or 20/50/30 would be much easier IMO, although given I find it hard to get carbs that high on root veg alone, 20% carbs would have involve either a fair amount of fruit, or sweet potatoes/white rice/lots of carb-heavy summer squash

I agree with most of the article. CCG I've wondered about how groups like the Inuit manage on ketogenic diets long-term. I suppose if it causes infertility in a subset of women, that would be selected against very rapidly!

I also think 20-65-15 would be hard to achieve in practice. At the moment I'd be eating 20-25% carb, 50-60% fat, 20-25% protein, and I work quite hard at eating fat.

I just finished reading The Perfect Health Diet and found it quite interesting. I have a few a few quibbles though.
- I think their idea of glucose deficiency being a big problem is over-done. The body works at keeping blood glucose in the correct range, and other than possibly putting an extra workload on the liver, I can't see that it makes much difference where the glucose comes from.
- Likewise I think calling fructose a poison in the same breath as grains, legumes and vegetable oils is over-sold. I think they're American, which might be why they're going so strongly against it. Obviously the amount of fructose most Americans eat is toxic! But I don't believe a few pieces of whole fresh fruit a day will kill me. That wouldn't make sense - we evolved from fruit-eating primates - why should fruit suddenly become toxic? And if it was toxic, why would we recognise fruit as tasty? It's been part of our available food for a very long time.
- My main beef with the book is they make healthy eating seem so complicated. After reading the book, you'd think it was a miracle human beings could survive before the advent of nutrition science. I certainly wouldn't recommend it to a non-paleo friend on those grounds alone.
However, I have learned a few things and decided to make some minor adjustments to my diet as a result of reading the book, so it was worth reading.

Quote from: celticcavegirl on January 11, 2012, 04:41:34 AM

Interesting article.  I would definitely support the "Long term ketogenic diets can lead to problems where the body thinks its starving and down-regulates thyroid function" statement

Has this been observed in a real world setting?

There is some evidence.  There was a study done on the ketogentic diet for epilepsy, on a group of teens.  Around 50% of the female subjects experienced menstrual irregularities or amenorrhoea.

I'm not sure that the body 'thinks it's starving' but it's all to do with leptin, t3, reverse t3 and t4.  Leptin deficiency for some reason means that the liver struggles to convert rt3 to active t3, instead it hangs around as r3 and t4.  This in turn affects the production of other hormones including oestrogen and progesterone.

There are also a lot of reports of ladies losing their cycle on low-carb diets, from paleo to primal to atkins, and it can't always be explained by rapid weight loss (Personally, I lost only about 8 pounds on paleo, and probably only 5 lbs of actual fat.  I was also unable to lose any more weight despite cutting cals to around 1000 a day for about 6 weeks and eating almost zero carbs (this was last winter))