A low protein diet (9% of total calories) caused changes in testicular epigenetics and males had offspring that were overweight with symptoms of type 2 diabetes and reduced activation of genes which regulate fat metabolism (mouse study).
The low protein diet changed the testicular expression of many folate-cycle enzymes (ie. Dhfr, Mthfr, and Mtr) and also changed DNA methyltransferases resulting in global hypomethylation.
This study was done in animals and further research is necessary to determine how much of this study’s findings can be translated to humans.
That’s interesting, given that Valter Longo’s Longevity Diet recommends protein as 10% of total calories. (Of course, optimizing offspring for efficient calorie processing when protein is limited may be a good idea in evolutionary time frames.)
I wonder what protein is as a % of calories in average forage for a wild mouse. Also, I wonder how well the lab mouse model reflects human outcomes for comparable diets.