He doesn't actually say "it's hard on the body." (He does say that about eating too much protein, but not about eating too few carbs.) He just says that it's not necessary for health and weight loss, and that it's not supposed to occur for people on the Optimal Diet once their bodies have adjusted, which can take 1-8 weeks depending on one's age and health history.

It's basically the same thing that Dr. Lutz says in Life Without Bread: Ketosis isn't something to be afraid of, but it's not something you should aim for, either.

yes, but once the body has adapted to using ketones for some or most of it's energy purposes ketones are no longer spilled but recycled - so one is not 'in ketosis' - i.e. spilling ketones. This can happen on zero carbs and also slightly higher amounts.

I think this question about why he would say something like that keeps coming up because for some people here the difference between say 20g and 70g of carb DOES seem to make a difference for weight loss (and it can go either way!). There even seems to be a difference for some between 20g and going even lower.

I think this is missing a decent enough explanation. I think it has to do with having enough glucose to fully metabolize fatty acids. That glucose can be found from excess protein, or from carbs. If there is not enough glucose from either source, then ketones are used for energy. Dr K's diet is low in protein, as in, there is no excess to provide glucose from gluconeogenesis. To prevent the person from running off ketones, carbs are used, so the body runs off fatty acids that are FULLY BURNED, not ketones, which are made from incompletely metabolized fatty acids.

Whatever the explanation, he obviously feels it is much better to use carbs rather than protein to provide glucose.

And the other issue is, why is it that some people don't lose fat when they are trying to use excess protein as their source of glucose? I.e. very low carbs, lots of protein, lots of fat. The people who have had success on Dr K's diet seem to do better using carbs for glucose, and not protein.

These ideas I have been discussing elsewhere so they are obviously not 'hard science' I'm just throwing it out there because it would be a shame not to explore this further.

Usually because they are consuming dairy.

Yes, well, seeing as this is the paleo forum I'm not going to tackle that one!

Actually - yeah I'll bite. I do know of people who gained, on zero carbs, with no dairy. So there!

Sorry, didn't mean to be quite so obnoxious. I see you said 'usually' - which seems to be true.

Some of the peeps doing Dr K's diet are still eating dairy but are losing with lower protein and higher carbs....

You just never know, though. I dropped dairy to follow the Neanderthin plan to try to break a long stall. But it didn't do me any good. I was just as stalled on the Neanderthin plan as I was when I was having dairy, but not even enjoying life to boot.

Right now I'm trying out the Kwasniewski Optimal Diet to see if cutting back on my protein will break a stall, as it seems to have done for many people.

Who?
I would like to know more, as I have never seen this happen. It's almost physically impossible if fat is high..

I know of two women. One on the zerocarbage forum, and at least two on the nocarber forum. One was trying and trying for a VERY long time, and just kept gaining bodyfat. She only lost on very restrictive calories - which bounced back again once she ate more again. All meat/fat. I don't know how much fat she was eating, but she definitely wasn't low fat or anything. Another one gained for a few months before throwing in the towel.

sorry, that makes 3 women.

Make that four. I gained on ZC and quit. I finally lost the 7 pounds I gained by following the Optimal Diet ratios- upping carbs (30-40) upping fat (tons) and lowering protein (50-60).

I can't say that I find any of the explanations as to why this would happen very convincing but I'm happy to lose the weight that just wouldn't budge for over a year.

*baffled by some peoples weird bodies and wanders off*

I don't gain on very low carb, but I stop losing after I hit a certain point, which is a good 20 lbs above my ideal weight (yes, even considering my age).

Although I can verify that next to carbs, dairy makes me gain weight really fast. Now I can see why they force feed it to those Mauritanian girls to fatten them.

For the past two or three years, I've gained about 10 pounds every fall (and lost it in the summer). The only dairy I eat is ghee, and my carbs are usually around 10-15g a day. I only introduced ghee after a long period without it, and could not detect any dairy reaction. I wouldn't be surprised if my 2007 gain was totally dairy free. My fat intake is always over 70% of calories, and I try to keep it near 80%. 75%-77% is typical.