With regard to soy, there is good and bad.
http://diabetes.diabetesjournals.org...57/5/1176.fullDietary Phytoestrogens Activate AMP-Activated Protein Kinase With Improvement in Lipid and Glucose Metabolism
OBJECTIVE— Emerging evidence suggests that dietary phytoestrogens can have beneficial effects on obesity and diabetes, although their mode of action is not known. Here, we investigate the mechanisms mediating the action of dietary phytoestrogens on lipid and glucose metabolism in rodents.
RESEARCH DESIGN AND METHODS— Male CD-1 mice were fed from conception to adulthood with either a high soy–containing diet or a soy-free diet. Serum levels of circulating isoflavones, ghrelin, leptin, free fatty acids, triglycerides, and cholesterol were quantified. Tissue samples were analyzed by quantitative RT-PCR and Western blotting to investigate changes of gene expression and phosphorylation state of key metabolic proteins. Glucose and insulin tolerance tests and euglycemic-hyperinsulinemic clamp were used to assess changes in insulin sensitivity and glucose uptake. In addition, insulin secretion was determined by in situ pancreas perfusion.
RESULTS— In peripheral tissues of soy-fed mice, especially in white adipose tissue, phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase was increased, and expression of genes implicated in peroxisomal fatty acid oxidation and mitochondrial biogenesis was upregulated. Soy-fed mice also showed reduced serum insulin levels and pancreatic insulin content and improved insulin sensitivity due to increased glucose uptake into skeletal muscle. Thus, mice fed with a soy-rich diet have improved adipose and glucose metabolism.
CONCLUSIONS— Dietary soy could prove useful to prevent obesity and associated disorders. Activation of the AMPK pathway by dietary soy is likely involved and may mediate the beneficial effects of dietary soy in peripheral tissues.
So we see soy increases AMPK activity, specifically it increases it mainly in the liver and in white adipose tissue. Soy also increased uncoupling in white adipose tissue by +64%! So it looks to be great for someone looking to build lean muscle and stay lean.
But what about its effect on endogenous hormone production?
And then enters the bad
Overall, small amounts are probably fine but I would not make soy a staple in my diet. Now on edamame, whenever I go out for sushi i will munch on them as I find them to be delicious! But again by no means would I make soy a staple but every now and then is probably fine.Clinical and biological activity of soy protein powder supplementation in healthy male volunteers.
PURPOSE: To determine if a commonly used soy protein supplement exhibits biological activity in vivo and in vitro, we evaluated an over-the-counter soy protein powder supplement using blood from healthy male volunteers and in an estrogen receptor in vitro assay. SUBJECTS AND METHODS: We recruited healthy male volunteers 18 years of age or older that were in good health. Treatment consisted of consuming two scoops (56 g) of pure soy protein powder (Puritan's Pride, Oakdale, NY) daily for 28 days. Serum testosterone and luteinizing hormone (LH) levels were collected on days -7, 0, 14, and 28 of therapy, and day 42. A reporter estrogen receptor (ER) assay was used to determine the effect on ER-beta and ER-alpha in vitro.
RESULTS: Twelve subjects were enrolled with a mean age of 32.25 years (range 25 to 47). Serum testosterone decreased 19%(+/-22%) during the 4-week use of soy protein powder (P = 0.021) and increased within 2 weeks after we discontinued soy protein powder. Serum LH concentrations decreased during the 4-week use of soy protein powder then increased within 2 weeks after we stopped the soy protein powder, but the changes did not reach statistical significance (P = 0.20). Soy protein powder was found to induce agonist activity to ER-beta using a reporter estrogen receptor assay in yeast.
CONCLUSION: Soy protein powder decreases serum testosterone levels in healthy men and acts as an ER-beta agonist; the significance of this biological effect with respect to cancer prevention needs further study.