Postby shooraijin » Sat Sep 24, 2005 7:47 am
Here's an MD take on it, since you asked.
Atkins induces a metabolic state called ketosis which occurs when the body is starved for carbohydrate fuel. At this point, it turns to other sources of energy.
What you're describing is the starvation reaction when no more sources are coming in, and the body is forced into catabolism, i.e., consuming its own proteins (usually starting with blood albumin, and then turning to other sources such as muscle). Fat metabolism requires that your metabolism be ramped up already, which is why fat persists in starving people while their "carcass" proteins are consumed instead -- it's easier and requires less metabolic power. You have to exercise or otherwise be in an altered metabolic state to get rid of fat.
Atkins is *not* a starvation state, although it's certainly not a normal state. It forces you into ketosis by denying the body carbohydrates, but at the same time you get a high protein source through what you eat. So, forced into ketosis, the body instead burns the proteins you're taking in. These are turned into water soluble ketones and used as an alternative source of fuel.
Much to the chagrin of traditional nutrition, Atkins has been repeatedly shown to induce weight loss (long term studies are less clear, but the effect does persist for several months or more) in multiple studies -- i.e., it does work! --, but the mechanism is actually quite simple. Atkins himself theorized that the weight loss was due to the ketones being passed in the urine, so you lose calories literally by going to the bathroom. He also theorized that the proteins take more energy to burn, but if so, why would a starving body resort to that? In fact, a twin study showed that the difference in metabolizing the two was barely around 20 calories, and not a single calorie wound up in the urine (as you would expect -- why would a starving body waste calories?). This research, last I checked, was still in progress.
The real story potentially is, people on Atkins diets ... eat less. It's not the fat, it's the protein. High protein foods seem to induce earlier satiety, and people consume less of them, meaning they're taking in less calories. A Danish study monitoring people on simply a high protein diet had similar weight loss.
Oddly, the fat has not seemed to increase Atkins dieters' risk of heart disease ... so far. However, their cholesterol numbers were bafflingly good for what they were eating.
The jury is out on the diet, and it remains tremendously controversial, but it is not a catabolic state (so not "cannibalism" as it were).
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