Understanding the importance of dietary fat has grown beyond energy metabolism to recognition of the complex roles of fatty acids, particularly the ω-6 and ω-3 fatty acids in membrane lipids, inter- and intracellular communication and in regulating gene expression.

The ω-6 and ω-3 fatty acids accumulated in developing tissues depend on the fatty acids transported across the placenta and secreted in breast milk. These in turn are dependent on maternal fatty acid intakes, which have changed dramatically in the past century with current western diets high in ω-6 linoleic acid and low in ω-3 fatty acids.

High intakes of ω-6 fatty acid and low intakes of ω-3 fatty acids compromise long-chain ω-3 fatty acid accumulation in tissues, and this is avoided by dietary docosahexaenoic acid.

In addition to the well-known roles in neural development, newer studies are beginning to question the importance of ω-3 fatty acids as a contributor of metabolic development in other organs, with possible implications for the development of feeding behavior and integration of the nutrient energy supply.