[matwood]

So eating mostly meat just makes it easier to consume fewer calories by default.

This is probably the most important statement in the entire thread. All of these fad diets basically trick the dieter into eating less calories. When Lustig, etc... cite various studies those studies never seem to account for overall caloric intake. Person A cut carbs, person B didn't, person A lost weight ergo carbs are bad. Yeah, it doesn't quite work that way. Saying that cutting calories will help a person lose weight doesn't sell books so authors have to pick something to demonize.

HFCS is a popular thing to demonize now. Is it surprising to anyone that if a person cuts out 4-6 sodas/day that had ~200 calories each that said person is going to lose weight? It had zero to do HFCS and everything to do with cutting out ~1000 calories/day. Again, that doesn't sell books or speaking engagements, but declaring X as evil does.

[sixbrx]

No it's a jump to a conclusion at least, and according to a recent study may be false. http://jama.jamanetwork.com/article.aspx?articleid=1199154.

The study seems to indicate that low carb diets actually do trigger more calories to be burned for the same level of activity, about 430 additional calories per day. It's too early to tell if this affect is real (larger study needed), but the results are interesting.

[Heinleinian]

This is what drives me crazy about the dieting issue. People will cite a study that involves 21 people. 21! Think of all the pain caused by people being overweight, and the insane costs imposed on our healthcare systems. With all that pain and cost, we can't come up with studies with larger sample sizes? Show me a double-blind study with 10,000 people and I'll start to take it seriously.

[rprasad]

Low carb diets also increase metabolic stress (specifically ketosis), which is one of the suspected reasons for the additional calorie burn. Ketosis over short periods is good, but scientists differ on whether it is safe in the long-term. For diabetics (Type I or II), ketosis is not safe, as the body does not have the proper insulin response to maintain safe levels of ketosis.

[KingMob]

Are there any studies on ketosis and diabetes? Because one of the primary drivers of insulin resistance in type 2 diabetes is being overweight. So, even if ketosis were bad, if losing weight improved your insulin sensitivity, it might still be worth it. Obviously, this shouldn't apply to type 1 diabetics, though.

[Heinleinian]

I'm sorry, this needs a citation. I'm not trying to be a jerk, it's just that with a subject this controversial you can't simply assert claims like this.