Nutrition studies will often use people as their own controls because of the significant variability between people. Nobody is willing to fund nutrition research with "perfect" studies, so researchers do what they can (especially when they are known to have hypotheses counter to the orthodox view).

On their books, I think that would be a ridiculous thing to reject people's findings for. Almost every academic has written a book at some time. Instead, we need to recognize the possibility of a bias inherent in every researcher and look to the study design, execution, and conclusions to see if they hold. Phinney and Volek are in a different class when it comes to their books and their ideas than is, say, Robert Lustig.

What would a control group have added? If you boil water in a beaker, do you need a control beaker where you monitor the temperature but don't light the Bunsen burner?

Also, how would you run a double-blind test of the foods people are eating? It's pretty hard to disguise steaks ;-)

Most nutritional studies are observational, so the numbers are not very reliable. In this case, "subjects were provided with all food for 18 wk, which was prepared and packaged by staff in our research kitchen." That's one reason why the numbers were so small, though it would have been better if they'd been bigger.

The most reliable evidence would come from controlling what people ate and what they did. I'd have thought this would be something that could be done with volunteer prisoners.