Okay, the formula for FEP reduction on the wiki seems to be outdated.
Probably because of this change:
viewtopic.php?f=39&t=65224"Took some steps to redefine the food variance bonus. The effect is now reduced for each new food type you eat, resetting when you level up."
Probably new formula:
Fₙ = M - E*sqrt(M) * Σ(k=1→n)(1/sqrt(k))
Where:
Fₙ = current stat cap after eating n unique foods
M = original stat cap
E = Variety Bonus value based on the Hunger Level table (
https://ringofbrodgar.com/wiki/Hunger)
n = number of unique foods eaten
Example:
M = 28 (my current highest stat, e.g. STR)
E ≈ 1.097
Base reduction:
E*sqrt(M) = 5.81
Food #1:
28 - 5.81 = 22.19
Food #2:
22.19 - 5.81/sqrt(2) = 18.08
Food #3:
18.08 - 5.81/sqrt(3) = 14.73