*UPDATE* Okay, so since I've been getting into fitness and nutrition from a skeptical, rational, empirical and Bayesian point of view, I've found out the diet the documentary's OP is advocating. It's called the "Paleo Diet" for those who might be wondering.
From Alan Aragon (read: a very smart nutritionist):
"The present decade has just begun, and eating clean has taken some interesting directions. One is an appeal to imagination about Paleolithic eating habits, which eliminates the consumption of grains, legumes, dairy, added salt, sugar, alcohol, and even certain vegetables. This definition of clean is perhaps the most logically inconsistent one. It emphasizes a prehistoric model, yet many of its proponents take an array of cutting-edge nutritional supplements, and use satellite technology to navigate their drive to the closest parking spot at the gym. Fruits and vegetables have always been a mainstay of clean eating, but pesticide-free produce is now somehow cleaner, pests and all. Another twist in the carbohydrate saga has snowballed as well. Insulin spikes from high-GI carbs were the bane of the 90’s. But now, fructose, a low-GI carbohydrate with minimal effects on insulin response, is now one of the top public enemies."-- http://www.wannabebig.com/diet-and-nutrition/the-dirt-on-clean-eating/
Incidentally, it turns out that, when controlled for Calories, HFCS is not more fattening than other sugars. My bad. Though it can indirectly cause you to eat more sweet/sugary foods as it tends to be in damn near everything courtesy of govco's corn subsidies, and because people just generally crave more of what they normally eat; and since sucrose, and other sugars tend to be very caloric 'empty' calories....there you go. And due to differences in rodent metabolic processes vs human ones.http://www.nsca.com/uploadedfiles/nsca/inactive_content/program_books/ptc_2013_program_book/aragon.pdf
(It's a powerpoint presentation, so it's a lot shorter than it looks).
I also doubt Tom's implied correlation/causation that it was eating grains/oils that caused people to become shorter and fatter. I mean, come on! Evidence or GTFO, Tom.