In this 2007 lecture, Greg Glassman stresses that to achieve elite athletic performance, one must weigh and measure the recommended diet of “meat and vegetables nuts and seeds some fruit little starch no sugar”. He asserts that while following the diet without weighing and measuring may keep a person from “optimize[ing] their output”, those who practice this gain the “accuracy and precision” needed to enter the “jet stream of elite performance”. Coach states that of the tens of thousands of people he has worked with, none have shown “superior capacity on a diet where they didn’t weigh and measure”. He says there is a “one-to-one correspondence between elite CrossFit performance and accuracy and precision to the consumption”.

Commitment and focus can overcome “genetic limitations,” citing athletes like Nicole, Amundson, Everett, and OPT as examples.

The two variables used for prescribing nutritional modifications are “ean body mass and activity level, with gender and age not being “germane”. The diet works by initially increasing the “burning of body fat,” leading to performance improvements until a plateau. When this happens, Glassman suggests doubling the fat intake to 2x or 3x, using performance to decide the best amount.

https://brokenscience.org/nutrition-lecture-part-2-eating-for-performance/