The thyroid hormones Thyroxine (T4), Triidothyronine (T3) and Calcitonin are made in the thyroid gland are responsible for regulating metabolism of every single cell in the body and for regulating body temperature. When too little T3 and T4 are released into the bloodstream resulting from an underactive thyroid, a variety of symptoms can develop. A poorly functioning thyroid – which is more common in women than in men – is likely to cause weight gain. Other symptoms of an underactive thyroid may include fatigue, slow metabolism, dry skin, forgetfulness, hair loss, depression and constipation.
The primary female sex hormone, estrogen, is actually a classification of three different hormones which are produced naturally – estrone (E1), estradiol (E2) and estriol (E3). Estradiol or E2 is the most important female sex hormone during a female’s reproductive years because it plays a role in reproduction, sexual function, bone health, brain function, body shape, fat storage, water retention, sleep quality, mood and complexion. In non-pregnant women E2 is produced by the ovaries and the adrenal glands and binds to estrogen receptors on cells. E1 is typically produced by fat cells but can be converted to E2 if need be.
If a female has too much or too little estrogen or if the proper ratio of estrogen to progesterone is disturbed, then it’s likely that weight gain particularly around the mid-section, hips and thighs will result.
Cortisol, also called the stress hormone, is released from the adrenal glands when the brain perceives some sort of physical or emotional threat. This hormonal stress response initiates a series of chemical messengers such as cortisol, adrenaline and norepinephrine to be released into the bloodstream which prepares every cell in the body to fight the threat or run away from it. While this stress response is engaged, heart rate and breathing increases, blood rushes towards the extremities and away from the internal organs, and the liver releases glucose as a source of quick energy.
This hormonal response is meant to be temporary and the body returns no a non-stressed state once the threat has passed. When the stressor is constant, however, cortisol is continuously released from the adrenals which can have negative consequences on the body and mind. Though the effects can vary, one popular consequence of high cortisol levels is weight gain.
When we consume foods and beverages that contain carbohydrates, our digestive system breaks those carbohydrates down into glucose which is then released into our bloodstream and utilized by our cells to fuel metabolic reactions. In healthy individuals, insulin is a hormone which is secreted by the pancreas in response to elevated blood glucose levels and delivers this glucose to your cells. When cells need glucose to function but there is not enough glucose in the blood for them to use for energy, insulin helps to release glucose from the liver. This response helps to keep blood sugar from getting too high or too low.
When too much glucose is consumed, the cells get their fix of energy but any leftover glucose in the blood is converted to fat and stored in the body’s fat cells.
As long as there’s insulin in the bloodstream the cells receive a signal to use blood glucose as energy rather than tap into body fat stores. The more glucose we eat in one sitting, the more insulin that is produced and the less our cells tap into our energy stores for fuel. Therefore, insulin prevents body fat from being burned.