We now know that major changes have taken place in
the food supply over the last 100 years, when food
technology and modern agriculture led to enormous
production of vegetable oils high in ω-6 fatty acids,
and changed animal feeds from grass to grains, thus
increasing the amount of ω-6 fatty acids at the level
of LA (from oils) and arachidonic acid (AA) (from meat,
This led to very high amounts of ω-6 fatty
acids in the food supply for the first time in the
history of human beings. Traditionally, animals grazed.
Grass contains ALA (ω-3), whereas grains, corn and soya
(which are now fed to animals) are high in LA (ω-6).
This imbalance in the amount of ω-6 and ω-3 fatty acids
is a new phenomenon that was never a part of human
evolution (figure 1, table 2). Human beings evolved
on a diet that had equal amounts of ω-6 and ω-3 fatty
acids. This balanced ratio of ω-6 to ω-3 is critical to
human development during pregnancy and lactation, in
the prevention of chronic diseases and in their management.
The typical Western diet now provides an ω-6 to ω-3 ratio
of around 16:1. High dietary intake of ω-6 fatty acids
as occurs today leads to increases in white adipose tissue
and chronic inflammation, which are the ‘hallmarks of obesity’.