Why? Well let's start with this. The assumption that a low carbohydrate diet is high in protein. It isn't. Or shouldn't be anyway. Unless you're a body builder. A low carbohydrate diet should be high in fat, not protein. The amount of protein they fed these 17 obese men is more than I consume on a typical day, some days by double. My protein intake is generally 70g to 130g. They fed these men 137-139g of protein.
My other main problem with this study, and why I think it's really irrelevant without even having to read it, is it's short duration and it's use of 17 men as subjects. Under powered and sexist to boot LOL
I think it's an obfuscation, what they're doing. They're attacking animal protein by attacking the low carbohydrate diet. In the case of the above study, I assume that they fed the people in the low carbohydrate group primarily animal protein. How else would you keep your carbohydrate count so low?
This whole attack on animal protein brings me back to something I was reading last night. They blame the protein in dairy for cancer. How did they come to that conclusion? By feeding people skim milk. The study I was looking at also lumped "all dairy" together and implied that "all dairy" had protein.
"Except for cheese with an insulin score of 45, milk and all dairy products including yoghurt, ice cream, cottage cheese, and fermented milk products have potent insulinotropic properties."1 [emphasis mine]
All dairy? Really. What about butter? Heavy cream? They have no protein. They have very little lactose, if any. You tell me how that's possible. I say it isn't. I say someone has an agenda and it's against animal products. Gee, I wonder who would have an agenda against animal products. I'll let you draw your own conclusions on that one.
"In a one-week intervention study of 24 pre-pubertal eight-year-old boys the effect of daily intake of 53 g of either lean meat or skim milk (1.5 l per day) was studied with regard to insulin and IGF-1 responses. In the skim milk group insulin significantly increased by 105% (from 22 to 45 pmol/l) and IGF-1 significantly increased by 19% (from 209 to 249 ng/ml) . There was no significant increase in either insulin or IGF-1 in the meat group."1 [emphasis mine]
Of course their insulin levels are higher in the skim milk group, the meat didn't have sugar (lactose) in it, and second of all, skim milk is not milk as you drink it from the cow. I mean, how stupid does one have to be? I went back and looked at the study that they're talking about, and talk about some confounding variables. The children were allowed to choose the diet they ate. Yes, you read that correctly. The children ate whatever they wanted, and simply were required to drink 1.5 liters of skim milk (12 of the boys) or eat 250g of low fat meat (the other 12). Consuming the milk apparently raised their IGF levels. But did it? Was it the milk? The protein in the milk? The lactose in the milk raising their insulin levels? The lack of fat in the milk so there was nothing to mediate their insulin levels? Some other dietary factor since there was no set diet? I mean, it could have been anything. I won't even get into the fact that it's under-powered and was only one week in duration.
Is drinking a large quantity of skim milk good for you? Hell no. I say you should never drink skim milk. If you want to consume milk, make sure it's whole, and better yet is straight from a dairy cow, not processed commercially.
"Milk consumption results in a significant increase in insulin and IGF-1 serum levels comparable with high glycaemic food. Insulin induces hepatic IGF-1 secretion, and both hormones amplify the stimulatory effect of GH on sebocytes and augment mitogenic downstream signalling pathways of insulin receptors, IGF-1 receptor and fibroblast growth factor receptor-2b."2
In other words, is it really the protein alone, or is it more likely that it's the lactose? And when they say "milk" do they mean skim, whole, or what? Because each kind should in theory have a completely different effect on your insulin levels.
One place to look for good information on what ketogenic diets do is in the one place that they're standard and acceptable. And that is in the treatment of epileptic seizures. About half of people, children included, will have a positive response to a ketogenic diet in helping control their seizures. This study found that IGF-1 was greatly reduced in a ketogenic diet, to the point where it stunted the growth of the children.3 A ketogenic diet is extremely low carb, basically near zero carb and low protein too (it's a high fat diet), and these children undertook it because being short is preferable to having seizures.
In fact, a lot of the literature is rife with making low carb synonymous with high protein. Like this study where they fed mice more protein than fat (46% v. 35% respectively). That's a lot of protein. Not to mention it throws in a confounding variable, so that when they declare that low carb diets do not slow tumor growth, one has to wonder how they know this. If they had fed them a higher fat diet, they might have noticed some benefit, since we know that protein affects insulin production, and insulin levels are probably a driving force behind a lot of nasty things. In fact, in this study IGF-1 was higher in the low carb group than in the high carb group, and I'm sure that is due to the protein, since insulin drives IGF.
So the point of all this? When eating a low carb diet, it should be primarily animal fat (none of that synthetic vegetable crap), your protein should probably be 15-20% depending on your activity level, and your carb count should be as high as you can tolerate and still lose/maintain weight. And don't listen to stupid journalists, and be wary of researchers, because I don't think most of them know what they're talking about.
1. Milk - The promoter of chronic Western diseases. Medical Hypotheses 2009; 72(6): 631-639
2. Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris. Experimental Dermatology 2009; 18: 833–841.
3.Growth dependence on insulin-like growth factor-I during the ketogenic diet. Epilepsia 2009; 50(2): 297-303.