Although I have not read anywhere in his articles about this connection, I came upon this study and immediately saw why Ray may be leaning towards a low(er) fat diet. Long story short - high fat diets increase serotonin synthesis and levels in plasma and tissues, and serotonin apparently directly contributed to obesity.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293832/
"...Expression of tryptophan hydroxylase 1 (TPH1), the rate-limiting enzyme in serotonin (5-HT) biosynthesis, and the 5-HT7 receptor (HTR7), which regulates mammary gland involution, were significantly increased in mammary glands of HFD animals. Additionally, we saw elevation of the inflammatory markers interleukin-6 (IL-6) and tumor necrosis factor-α (TNF- α). These results indicate that consumption of HFD impairs mammary parenchymal tissue and impedes its ability to synthesize and secrete milk, possibly through an increase in 5-HT production within the mammary gland leading to an inflammatory process."
The entire study is good read so I recommend reading it for those that are not bored by biochemical topics.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293832/
"...Expression of tryptophan hydroxylase 1 (TPH1), the rate-limiting enzyme in serotonin (5-HT) biosynthesis, and the 5-HT7 receptor (HTR7), which regulates mammary gland involution, were significantly increased in mammary glands of HFD animals. Additionally, we saw elevation of the inflammatory markers interleukin-6 (IL-6) and tumor necrosis factor-α (TNF- α). These results indicate that consumption of HFD impairs mammary parenchymal tissue and impedes its ability to synthesize and secrete milk, possibly through an increase in 5-HT production within the mammary gland leading to an inflammatory process."
The entire study is good read so I recommend reading it for those that are not bored by biochemical topics.