Insulin – High levels of insulin may contribute to our fatness. Insulin, the blood sugar regulator, is pumped out in excessive amounts as it tries to reduce the abnormally high blood sugar that results from a high carbohydrate, low protein diet. We inevitably gain weight and become fat, and our cells become resistant to insulin and fat loss.
Cortisol – High insulin also increases the secretion of cortisol, our stress hormone. High cortisol causes a corresponding drop in the hormone dehydroepiandrosterone, which, among other actions, helps to increase muscle mass. More muscle mass is needed for fat loss, as it increases fat burning and reduce insulin. Chronic stress also activates all fat cells to store fat. The central fat cells, found mainly deep in the abdominal wall, have four times the cortisol receptors on their cell membranes. Each time we are stressed the cortisol-fat mechanism turns on and our body stores more fat.
Leptin – Another hormone – leptin, produced by body fat – is critical in telling the body when to eat and when we are satisfied. Scientists have learned that in some people the message of satiety is not heard and fat cells send out more and more leptin, causing resistance to leptin, increased food cravings, and the desire to continue eating. In other people, leptin levels are low due to zinc deficiency.
Serotonin – The hormone serotonin, a neurotransmitter in the brain made from the amino acids found in proteins, is also involved in signalling satisfaction. Low serotonin levels cause depression, obesity, lethargy, a preference for refined carbohydrates, and overeating because the brain senses it is starving. A diet that restricts protein-rich calories causes serotonin levels to plummet. People who are hyper-secretors of cortisol also exhibit suppressed serotonin levels.
Thyroid – Low thyroid – called hypothyroidism – affects approximately 30 percent of the population in Canada. Low thyroid reduces our fat burning rate and causes fatigue, inhibiting energy levels.