This 2021 rodent study investigated effects on offspring of maternal high-fat diet (HFD) during gestation and lactation, and offspring HFD during young adulthood:

“We found that gestation was the most sensitive period to induce obesity in late life, and there was no difference between sexes in chance of obesity. Furthermore, we found that lactation and administration of a HFD post‐weaning increased incidence of lipid metabolism disorders and obesity in offspring.

There are different windows of opportunity for programming epigenetically labile genes. Some studies support the alteration of epigenetic status during development as an important cause induced adult obesity.

Gestation is considered as the most sensitive period because high DNA synthesis and DNA methylation patterns are established for normal tissue development during the embryonic period. These two programming events are the times when the epigenetic state changes most widely in the life cycle.”

https://onlinelibrary.wiley.com/doi/10.1111/jcmm.16551 “Gestational high-fat diet impaired demethylation of Pparα and induced obesity of offspring”

Hey mothers! Do what you please. But don’t turn around and deny consequences of your behavior and choices on your descendants’ physiology and behavior, and possibly those of further descendants.

Gestation, birth, infancy, and early childhood are critical periods for humans. There’s no going back to correct errors and problems.