EDIT 1/8/2010: Step 6 used to be intermittent fasting. I now view IF as a useful fat loss technique, and no longer see it as necessary to achieve the EM2. Ketosis may prove to be therapeutically useful ( already is for brain degenerative disorders) for cancer prevention or treatment, but I do not think being in ketosis or frequent IF is necessary to be healthy generally. I still believe in the practical advantages of using animal fats as a fuel source.
Step 6 is a cultural counterweight to all the stupid advice you see about "frequent healthy snacks" in the mainstream media. We are told to eat frequent snacks because the standard american diet with 55% carbs has you metabolically and emotionally tethered to frequent boluses of glucose.
Go watch a kid's soccer game- they can't play for 15 minutes without a break for cookies or corn-syrup-laden juice boxes or gatorade - our children are sugar junkies and the advice to eat frequently is just advice to not stray too far from your dealer so you can get a fix when your blood sugar starts to crash!
So I agree with Gary Taubes that we should listen to our bodies, but only after we have kicked the cocaine, the alcohol, the cigarettes the sugar, and the cereals.
Otherwise our bodies are likely to tell us we need something that is not good for us.
My experience has been that without the frantic hunger of a glucose-eater, I can eat at whatever time is convenient. I eat the right types of foods, with no measurement, counting or weighing whatsoever, and I stop eating when I am satisfied. My weight has been absolutely stable eating this way for almost 2 years, putting the lie to the idea that you need to "count calories' to keep weight off. Our weights and appetites are under hormonal control, and our bodies regulate them quite precisely at given macronutrient ratios and the hormone levels that result.
I began to fast spontaneously a few months into eating low carb (my percentages are about 65% fat, 25% protein and 10% carbs). On LC, the character of hunger changes completely. Without swings in blood glucose, and with cellular adaptation towards fatty acid metabolism, the "sick' sort of hunger that most people think of as hunger goes away. I find that I can arbitrarily fast for up to 18 hours with no discomfort whatsoever. If the goal is to keep your insulin levels low, it is only logical that increased intervals between meals increases the amount of time spent in the fatty-acid-fueled state, and less in the pro-inflammatory, oxidative stress-causing state where your body is trying to deal with excess calories, especially from glucose. I believe intermittent fasting and infrequent meals decrease the hormonal signals that lead to disease and the hormone sensitive degenerative diseases that we think of as "aging".
Advantages of infrequent meals:
1) Enhanced metabolic training in the direction of fat metabolism
2) Lower insulin levels and fewer insulin related diseases (Metabolic syndrome, degenerative diseases, Alzheimer's, common cancers)
3) Greater tolerance for fasting makes it easier to tolerate not eating - this give you "metabolic headroom" -it makes you more functional and resilient - You are a Porsche with a 40 gallon gas tank instead of a truck running on lead acid batteries.
4) If you exercise while fasting, the lack of insulin in the fasting state improves the fat-mobilizing and insulin-sensitizing benefits of the exercise.
I eat around noon and again about 9 pm most days. So every 24 hours has a 15 hour fast and once in a while up to 18 hours. Please understand that this is in no way uncomfortable and my weight has been stable at 157-158 lbs for over year. It's not some kind of deprivation or an ascetic experience. I have no idea if this is better than 3 meals a day with a 24 hour fast once a week. This is just what I do spontaneously, but my reading of the literature backs it up as beneficial.
I am sure my regime is healthier than the 5 meals a day "The Zone" or other pseudoscientific diets tell you you must have, or the advice to snack constantly I get from brochures at my local YMCA. Hunter-gatherers tend to eat a few leftovers in the morning, hunt all day and then have a big meal at the end of the day - sounds pretty similar. I doubt if in paleolithic times they very often fasted on purpose, but I do believe they were adapted to food scarcity.