Ketogenic diets display the "metabolic advantage" and anticancer effects in mice

While browsing Pubmed for recent studies on ketogenic diets I came across Carbohydrate restriction, prostate cancer growth, and the insulin-like growth factor axis. I only read the abstract so far, because the full text costs more than I want to spend, but the abstract certainly contradicts those who say that only calories count.

The researchers put 75 Severe Combined Immunodeficiency (SCID) mice on three different diets:

1. No-carbohydrate ketogenic diet (NCKD) providing 84% of energy as fat, 0% as carbohydrate, and 16% as protein.
2. Low-fat diet providing 12% of energy as fat, 72% as carbohydrate, and 16% as protein.
3. "Western" diet providing 40% of energy as fat, 44% as carbohydrate, and 16% as protein.

They let the low-fat dieters eat ad libitum, the others were fed using a modified-paired feeding protocol. After 24 days on the diets, all mice were injected with prostate cancer cells. When tumors approached 1000 mm, they sacrificed the animals.

RESULTS: Despite consuming equal calories, NCKD-fed mice lost weight (up to 15% body weight) relative to low-fat and Western diet-fed mice and required additional kcal to equalize body weight.

Get that? They had to feed the NCKD mice more food calories than the other mice to maintain weight.

Now according to all the "experts" who criticize Taubes, only calories count and reducing carbohydrates confers no metabolic advantage. They claim that people always misrepresent their caloric intakes and eat less than they think when eating low-carbohydrate diets. But these mice didn't fill out any questionnaires misrepresenting their caloric intakes. Their food intake was tracked. Where did those extra calories go?

Well, I would venture this: Since the mice eating the low-fat and "western" diets had high carbohydrate diets, they had higher insulin levels, so they had a higher proportion of their caloric intake going into storage (fat), while the NCKD mice had a low insulin level so their calories went into energy for both basal metabolism and activity.

Besides displaying a "metabolic advantage" (i.e. unexpected weight loss at a caloric intake that did not cause weight loss in high-carbohydrate mice), the NCKD had tumor volumes were 33% smaller than Western mice (no different from the low-fat mice). The NCKD mice also had the longest survival, followed by the low-fat mice.

So much for T.Colin Campbell's claims that high-fat dieting will promote cancer while Chinese-style low-fat dieting produces the best health and longest lifespan. He never did think to test a no- or very low- carbohydrate diet on his aflatoxin-poisoned animals.

In addition,serum insulin-like growth factor binding protein 3 measured highest and IGF-1:IGFBP-3 ratio lowest among NCKD mice.

In contrast, serum insulin and IGF-1 levels were highest in Western mice.

Not only that, "NCKD mice had significantly decreased hepatic fatty infiltration relative to the other arms."

"CONCLUSIONS: In this xenograft model, despite consuming more calories, NCKD-fed mice had significantly reduced tumor growth and prolonged survival relative to Western mice and was associated with favorable changes in serum insulin and IGF axis hormones relative to low-fat or Western diet."

It appears this team published a similar paper in the June 1, 2009 issue of Cancer Prevention Research: The Effects of Varying Dietary Carbohydrate and Fat Content on Survival in a Murine LNCaP Prostate Cancer Xenograft Model.

In this second study they fed the mice "to maintain similar average body weights among groups." This showed that you can get a mouse to maintain or even gain weight on a ketogenic diet if you make it eat enough. As I have said, no matter the source, calories do count, but the carbohydrate calories count more than fat or protein calories.

Results: NCKD mice had significantly reduced median serum insulin, insulin-like growth factor I (IGF-I), IGF-I/IGF binding protein-1 ratio, and IGF-I/IGF binding protein-3 ratio compared to moderate-carbohydrate (43%) diet mice. In addition,tumore in the NCKD mice had a reduced activity of pathways associated with blocking programmed cell death (antiapoptosis), inflammation, insulin resistance, and obesity.

And this was in mice, a species not adapted to a low-carbohydrate diet. Unlike humans, mice don't have an evolutionary history of dependence on low-carbohydrate diets. The myth that low-carbohydrate or ketogenic diets destroy your health continues to crumble.