We have received a fair number of inquiries about whether it is necessary to add additional leucine to shakes, as recommended in the recipe for Power Up Shakes in 6WC, if the shake powder itself lists 2000 or 2500 mg leucine per serving on its label.

The short answer is:  it depends.  For some people it will be necessary to supplement leucine and for others it may not be, but at no time is it problematic to add some.

Numerous medical studies (particularly those of Dr. Donald Layman) have shown the benefit of an intake of 8 to 12 grams of leucine per day when dieting in helping to preserve the body’s lean tissues while encouraging greater fat loss, both goals of those trying to trim a middle aged middle.  More importantly, as we just learned in new data Dr. Layman presented to members of the Metabolism Society at their meeting last week, there is a protein/leucine threshold per meal that is required to trigger protein synthesis (ie, muscle building, repair, and maintenance) of about 20 to 30 grams total protein, with about 2.5 grams of that, minimum, as leucine.

Whey protein itself is a rich source of this essential amino acid, containing about 10% leucine by weight, which is why it’s the base we recommend for the Power Up Shakes on weeks 1 and 2 of 6WC.  The amount of protein (and thus leucine) in a scoop or serving of whey protein powder varies with the product and the amount of protein powder needed per serving varies with the size of the individual consuming it.  Most whey protein powders contain in the range of 18 to 20 grams of protein per scoop, which is usually listed as a ’serving.’

A typical scoop of whey protein powder would then have about 1.8 to 2 grams of leucine per serving.  Thus three shakes a day would provide 5.4 to 6 grams of leucine to those whose protein requirement would be met by the single serving of that powder–still a bit short of the 8 to 12 grams per day recommendation.  Those with bigger protein requirements, who might need 2 or even 3 such servings of protein powder, would get double or triple the amount of leucine and would fall easily in the total daily recommendation of 8 to 12 grams, even before counting whatever the leucine content of their 6WC protein meal might be. Leucine is present in protein-rich foods, such as meat, fish, and eggs, which adds another 1.5 to 2  grams per 3 ounce portion–about what a person with a small protein requirement might consume at a meal —but even that would put that smallish person barely into the recommended range.  So it’s mainly smaller people who may need the supplemental leucine.

However, since the 6WC was written based on exactly the diet Mike and I used ourselves to trim our middles in 6 weeks, it’s in the shake recipe, just as we used it.  Since we wanted to maximize the results we would get in a short space of time, I wanted to be sure I had enough leucine to meet those requirements and even Mike (who is a 2 1/2 scoop of whey protein powder per shake guy) added leucine to each shake.

If you are absolutely certain you are getting a total of 8 to 12 grams per day of leucine from the shake powder you use and the foods you are eating at your food meal in weeks 1 and 2 (or solely from the foods you are eating during the meat weeks) then you needn’t add extra leucine.  If, like us, you want to be sure, then add it.

And so we are back to the short answer we began with.  Some people (those with small protein requirement per meal) will really benefit from adding the extra leucine even to a whey-based shake that say it contains 2500 milligrams per serving.  Those who eat plenty of leucine containing foods may not wish to do so. Others, like Mike, whose protein requirement will dictate that their shakes will meet or exceed the requirement of leucine may not require it, but may still want to add it as a measure of safety, as there’s no downside.

We have received countless letters from readers unable to find Enova oil in supermarkets any longer and wondering where to look.  Unfortunately, there is no where else to look.  The only commercially available source of diacyglycerol oil (DAG) was the Enova product.  In September 2009 the manufacturer voluntarily discontinued distributing the oil for reasons explained here, chiefly involving levels in the oil of potentially carcinogenic substances called glycidols.  The manufacturer stands behind the product and its safety, but is attempting to reformulate the oil to reduce these unwanted compounds.  Time will tell about whether they are successful in that endeavor.

Why did we recommend incorporating a small amount of this oil in the 6 Week Cure in the first place?  Accuracy. When we were under the time gun for filming our PBS healthy cooking show, Low Carb CookwoRx, we needed the quickest possible results.  At the time, the oil was readily available everywhere and the research that it might help to promote abdominal fat loss seemed both intriguing and solid.  In an effort to bring every possible tool to bear on our own middles in a very short space of time, we included it in our own Cure.  As the book was a direct outgrowth of our own experience, since we used it ourselves, we included the use of small amount of DAG in The 6-Week Cure book.

At best, the addition of DAG offers but a smidgen of help in reducing a middle aged middle and omitting it entirely won’t significantly change the results on the plan.

Thus our recommendation to the many readers who have written to ask what to replace it with is…nothing.  Simply follow the remainder of the plan and don’t worry about the DAG oil.