Soy = Low Thyroid Function = Low Metabolism = Low Energy
The goitrogens in soy are anti-thyroid. They lower thyroid function.
Soy goitrogens prevent the production of thyroid stimulating hormone, TSH, T3 (tri-iodothyronine) and T4 (thyroxine). T3 has 3 copper atoms. T4 has 4 copper atoms. Soy goitrogens prevent the absorption of iodine.
The authors did too, until they started in-depth reading and researching. Don't believe the false advertising.
...Of all the goitrogenous foods, soybeans pose the greatest threat. The antithyroid substances in soy are not destroyed by cooking.... ~ pg 141, Dr. Bruce Fife, The Coconut Ketogenic Diet, Supercharge Your Metabolism, Revitalize Thyroid Function, and Lose Excess Weight
Asian food lovers, please see important note at bottom on organic soy sauce, miso and tempeh.
....if you eat like most people, you're consuming soy in one form or another every single day...soy is used in a wide assortment of [processed] foods...it's even in baby formula... ~ Dr. Bruce Fife, ibid.
...At least 60 percent of the foods on America's grocery shelves contain soy derivatives - soy flour, texturized vegetable protein, vegetable oil, partially hydrogenated oil, soy protein isolate, etc. Almost every packaged, prepared food you pick up now  contains soy in one form or another... ~ Dr. Bruce Fife, ibid.
....it makes me wonder if part of the reason why we are experiencing a growing problem with hypothyroidism and overweight is due to the increasing amount of soy in our food supply... ~ Dr. Bruce Fife, ibid.
Dr. Kaayla T. Daniel on Sanitas Radio - The Whole Soy Story Interview: The Dark Side of America's Favorite Health Food
Book Reveiw: The Whole Soy Story
Soybesity: Soy and Weight Gain
Important Note: Naturally processed, fermented organic soy sauce, miso and tempeh are a few of the healthy soy choices as most of the goitrogenic (anti-thyroid) toxins have been neutralized in the fermentation process. Modern processed tofu is not a staple of any Asian diet. It's consumed in small amounts as a condiment.