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Why is soy limited in the challenge

A basic overview of a number of research articles has been complied below to explain why we have limited soy consumption in parts of our program, as well as some recommendations on the best types to consume. For more information please refer to the references provided, and as always, feel free to conduct your own research and make up your own mind. 

Many soybean products are processed for meal and oil (shortening, margarine, cooking oil & salad dressings). Soy lecithin is one example found in many foods and commonly used as an emulsifier, which means it helps oil and water mix together and stay stable. In the past, soy has been portrayed as a superfood, however, new evidence has emerged about the negative health impacts it can have. 

Health research into the dangers of soy

Research has concluded that there are a number of concerning factors surrounding the consumption of soy products. Impaired fertility and immunity (reference 1,2,3,4), thyroid disorders (5), cognitive impairment (6,7) and infant abnormalities (8,9), dominate these concerns.

The issues

The major concerns include the toxins, isoflavones, aluminium and manganese levels present in the soy beans, together with the fact that a large percentage of the world’s soy crops are genetically modified (10,11).

Soy products of concern include:

TVP (texturized vegetable protein) or soy protein isolate
Soybean oil
Soy milk
Soy cheese, soy ice cream, soy yogurt
Soy protein
Soy infant formula.

Better options for consumption

Fermented soy products such as:

Tempeh – fermented soybean cake that is firm and has a nutty, mushroom-like flavour 
Miso – fermented soybean paste that is quite salty and commonly used in miso soup
Natto – sticky fermented soybeans with a strong, cheesy flavour
Tamari – fermented soybeans, salt & enzymes.

Soy alternatives


Soy bean oil for olive oil, or coconut oil
Soy milk for almond or coconut milk
Soy cheese, ice cream or yogurt for coconut ice cream/yogurt
Soy protein for amino-acid packed hemp protein
Soy infant formula for soy-free alternatives.


(1) Colborn, T., Vom Saal, F., & Soto, A. (1993) Developmental effects of endocrine-disrupting chemicals in wildlife and humans. Environmental Health Perspectives, 101, 378-384.
(2) Poon, B., Leung, C., Wong, C., & Wong, M. (2005) Polychlorinated biphenyls and organochlorine pesticides in human adipose tissue and breast milk collected in Hong Kong. Archives of Environmental Contamination and Toxicology, 49, 274-282.
(3) Irvine, C., Shand, N., Fitzpatrick, M., & Alexander, S. (1998). Daily intake and urinary excretion of genistein and daidzein by infants fed soy- or dairy-based infant formulas. American Journal of Clinical Nutrition, 68, 1462-1465.
(4) Mitchell, J., Cawood, E., Kinniburgh, D., Provan, A., Collins, A., & Irvine, S. (2001) Effect of a phytoestrogen food supplement on reproductive health in normal males. Clinical Science, 100, 613-618.
(5) Fort, P., Moses, N., Fasano, M., Goldberg, T., & Lifshitz, F. (1990) Breast and soy-formula feedings in early infancy and the prevalence of autoimmune thyroid disease in children. Journal of The American College of Nutrition, 9, 164-167.
Biochemical Pharmacology, 54, 1087-1096.
(6) White, L., Petrovich, H., Ross, G., & Masaki, K. (1996) Association of mid-life consumption of tofu with late-life cognitive impairment and dementia: the Honolulu-Asia aging study. Fifth International Conference on Alzheimer’s Disease, 487.
(7) White, L., Petrovich, H., Ross, G., Masaki, K., Hardman, J., Nelson, J., Davis, D., & Markesbery, W. (2000) Brain, aging and midlife tofu consumption. Journal of The American College of Nutrition, 19, 242-255.
(8) Cassidy, A., Bingham, S., & Setchell, K. (1994) Biological effects of a diet of soy protein rich in isoflavones on the menstrual cycle of premenopausal women. American Journal of Clinical Nutrition, 60, 333-40.
(9) Setchell, K., Zimmer-Nechemias, L., Cai, J., & Heubi, J. (1997) Exposure of infants to phyto-estrogens from soy-based infant formula. Lancet, 350, 23-27.
(10) McGraw, M., Bishop, N., Jameson, R., Robinson, M., O’Hara, M., Hewitt, C., & Day, J. (1986) Aluminum content of milk formulae and intravenous fluids used in infants. Lancet, 1, 157.
(11) Dabeka, R., & McKenzie, A. (1987) Lead, cadmium, and fluoride levels in market milk and infant formulas in Canada. J Assoc of Anal Chem, 70, 754-57.