Weight gain and loss is much more complicated than diet and exercise.

If only it were that simple!

The bottom line is this: we’re all biologically unique individuals. This is why there is no clear-cut, one-size-fits-all approach to health, weight loss included. We each thrive on different ratios of macronutrients (carbohydrate, protein, and fat), and have different metabolic rates.

Not only do we need to take our unique biology into consideration, but external factors as well — elevated stress levels and a lack of sleep are both known to promote weight gain, as does our everyday exposure to unhealthy chemicals.

A number of chemicals we come into contact with on a daily basis are considered “obesogens.”

Did you pick up on the word “obese” at the root of this word?

Obesogens are endocrine disruptors — meaning they interfere with the body’s natural hormone production — that have been clinically shown to increase wight gain and promote obesity.

By interfering with our hormones, obesogens:

• Encourage the body to store fat and re-program cells to become fat cells.

• Prompt the liver to become insulin resistant, making the pancreas create more insulin which turns energy into fat all over the body.

• Prevent leptin (a hormone that reduces appetite) from being released from fat cells to tell the body it’s full. This leads to overeating.

It’s important to note that weight gain is just one danger posed by obesogens and endocrine disruptors. These chemicals have been linked to an increased risk of reproductive diseases, endocrine-related cancers, behavioral and learning problems, and asthma.

Chemicals that have been linked to weight gain:

BPA | Used in plastic products and receipt paper

One study found that BPA triggers the release of nearly double the insulin actually needed to break down food.

To avoid BPA, choose glass whenever possible. Remember: BPA-free is a load of B(P)S and not necessarily as safer option. See these 10 Ways to End Your Relationship With Plastic for specific tips and suggestions.

Parabens | Used in the majority of personal care products

These preservatives mimic estrogen, high levels of which can cause insulin resistance and increased body fat.

Choose paraben-free beauty and skincare products. Learn more about The Ugly Side of the Beauty Industry some of my favorite non-toxic beauty and skincare alternatives.

Phthalates | Uses in plastic products like toys and artificial fragrance

A number of studies in humans have shown that phthalates levels in the body are associated with increased belly fat, waist circumference, and insulin resistance.

To avoid synthetic fragrance, choose natural beauty and skincare products as well as home cleaning products (including candles).

Triflumizole | Fungicide using in conventional farming

A study published in Environmental Health Perspectives has linked triflumizole to weight gain.

To avoid triflumizole, choose organic produce whenever possible, especially leafy greens. Check out these 7 Ways to Save Money on Healthy, Real Food to stay healthy while sticking to a budget.

PFOA | Used non-stick pots and pans

In a study in mice, exposure to PFOA during development lead to increased insulin levels and body weight during adulthood. Another Danish study found that mothers with the highest blood levels of PFOA were three times more likely to have overweight or obese daughters 20 years later than mothers with the lowest levels. Though these studies don’t necessarily seal the deal, there’s no reason not to avoid this chemical since safer alternatives to non-stick cookware is readily available.

Check out Which Cookware is Healthiest? to find healthier alternatives.