1. Environmental Chemicals
Many environmental chemicals have resulted in weight gain when tested on animals in low, non-toxic doses. Examples include heavy metals, solvents, coolants, pesticides and plastics (such as BPA, used in food and beverage containers). Some of these chemicals known as endocrine disruptors can interfere with weight-controlling hormones. There is even evidence to suggest that exposure to environmental chemicals in the womb may be associated with obesity later in life.
Emulsifiers are chemicals which cause oil to mix with water. They are used in a wide range of processed foods including ice cream, mayonnaise, margarine, chocolate, bakery products and sausages. A mouse study published in Nature found that emulsifiers alter gut bacteria, causing inflammation. Mice fed water containing emulsifiers became obese and developed metabolic syndrome, a group of risk factors that increase the risk of heart disease.