About your hormones

How your hormones affect your weight

The Hunger Hormones – Ghrelin and Leptin

Hormones have a huge role to play in your weight and it’s management.  The two key hormones are Ghrelin and Leptin.  Both hormones are operating all the time (but in differing proportions) and both send signals to the brain.  When we are hungry ghrelin (also known as the hunger hormone) is secreted into the stomach and sends a hunger signal to the brain for us to eat.  In this situation ghrelin is dominant and leptin is less active. 

Leptin (also known as the satiety hormone) is made in the fat cells.  The more fat we have the more leptin is produced.  Normally as we eat the fat stores get replenished and the leptin increases to a point where it sends a signal to the brain to stop eating.  At this point the ghrelin decreases and hunger subsides.  See the image below.

Conflict can occur in morbidly obese people (or those who are genetically resistant) whereby during eating the ghrelin does not reduce as much as it should (so it still sends hunger signals) and the brain may not ‘read’ the ‘I am full signal’ from the leptin.  The result is overeating.

Leptin resistance

Leptin resistance occurs in morbidly obese people.  The more fat your body has the more leptin it produces.  In normal weight people this ensures that we stop eating when our fat stores are full.  With leptin resistance the brain stops listening to the leptin and the body takes on even more fat which produces even more leptin again, meaning that the body and brain enter a vicious circle. 

This is shown in the diagram below.

Leptin resistance is normal in two situations:  pregnant women who need to build fat and in adolescence where it is required for growth.

Tips for improving leptin sensitivity

Avoid heavily processed foods and simple  carbohydrates

Eat more anti-inflammatory foods

Exercise regularly

Get good sleep

Tips for improving ghrelin sensitivity

Avoid high-fructose corn syrup and sugar-sweetened drinks, which can impair ghrelin response after eating

Eat protein at every meal especially breakfast. This is good for satiety


Insulin is made in the pancreas and controls our blood sugar levels.  After we have eaten, the digestive system breaks down the carbohydrate and converts it to glucose.  This is absorbed through the wall of the small intestine and enters the bloodstream.  Once in the bloodstream glucose causes your cells to absorb the glucose and use it for energy.  If there is too much glucose in the bloodstream insulin signals for it be stored in the liver.  This is released when blood sugar levels drop, when we are stressed or if it is needed as an extra energy boost.

Insulin is the main fat storage hormone in the body and it tells fat cells to store fat.  It is also thought to influence the rate at which we burn fat.

If the cells become insulin resistant both blood sugar and insulin rise significantly.  If high levels remain the result can be many health problems including obesity and metabolic syndrome.

Insulin resistance can result from eating overeating too much sugar, fast food and refined carbohydrates.

Tips to improve insulin sensitivity

Limit sugar intake.  High amounts of fructose and sucrose encourage insulin resistance and increase insulin levels.

Reduce carbohydrate intake.  This can help reduce insulin levels.

Eat protein.  This will initially raise insulin levels but in the longer term the reduction in belly fat help reduce insulin levels.

Eat healthy fats.  Omega 3 fats found in fish can help lower insulin levels.

Exercise!  This has been shown to improve insulin sensitivity.

Cortisol and Neuropeptide – Y

These hormones are discussed in Module 10 – Stress


 This hormone is discussed in the Good Sleep topic below


Produced in the ovaries estrogen is the most important female sex hormone.  It regulates the female reproductive system.  High and low levels of estrogen can both lead to weight gain.  This hormone starts promoting fat storage at puberty.  It also stimulates fat storage in the first half of pregnancy.

Obese women tend to have higher levels of estrogen compared to normal weight women.

During menopause the main sites for fat storage shift from the hips and thighs to visceral fat around the abdomen.

Tips for managing estrogen

Fibre.  Eat plenty to help reduce estrogen

Eat cruciferous vegetables


Glucagon-Like Peptide-1 (GLP-1)

This is a hormone produced in the gut when it receives nutrients.  It plays a major role in regulating blood sugar levels, keeping them stable and it also makes you feel full.  It works by enhancing the secretion of insulin.  Glucagon-like peptide 1 also increases the feeling of fullness during and between meals by acting on appetite centres in the brain and by slowing the emptying of the stomach.

It is thought that too little glucagon-like peptide 1 released after a meal may increase the likelihood of, or worsen, obesity.

This is because glucagon-like peptide 1 reduces appetite after a meal. If the body releases less of this hormone, individuals may eat more during a meal and are more likely to snack between meals.

Tips for increasing GLP-1

Eat plenty of protein.  High protein foods like fish and yogurt are thought to increase GLP-1 and improve insulin sensitivity.

Eat anti-inflammatory food.  Inflammation has a negative effect on GLP-1 levels.  Berries, broccoli, and avocados etc. all help GLP-1

Eat leafy greens.  Greens like spinach and kale can increase GLP-1 according to research.


Serotonin is responsible for a number of functions in the body but is most commonly associated with mood, anxiety and happiness. It also helps with blood clotting and wound healing, sleep, eating and digestion.

Serotonin regulates nausea. Production of serotonin increases to help remove bad food from the body through sickness and diarrhoea.
It is mainly made in the gut from an amino acid called tryptophan.

Tryptophan is commonly found in proteins. Here are some foods that can help your serotonin levels:

Salmon, chicken (and other poultry), eggs, nuts, cheese, red meat, spinach, soy products, seeds and milk. Carbohydrate helps with the production of serotonin and so the protein and carbs are best eaten together.

Having a healthy gut is very important for serotonin production. Prebiotic and probiotic foods may help together with abstaining from damaging foods like artificial sweeteners, trans-fats, processed and refined sugars.


Dopamine is a neurotransmitter. It is known as the ‘feel good’ hormone since it is released in anticipation of something we find pleasurable. If you have a particular passion for say, chocolate cake and you expect to eat some soon your dopamine levels rise. They also rise as you are eating the cake.

Dopamine is involved in the cycle of motivation, reward and reinforcement. So it can help us form habits.

Dopamine doesn’t work alone but in tandem with other hormones and neurotransmitters like serotonin and endorphins.

Dopamine is involved in a number of functions in the body including:

Learning, planning and productivity.
Your alert level.

Focus and motivation.

Sleep and stress response.

Heart and kidney functions.

Blood flow and digestion.


As human beings we are programmed for survival. So we have an innate desire to reward anything that helps the species to survive and at the same time avoid pain. Endorphins do both: they reward activities that help our survival like exercise, eating and sex. But they also act as natural pain relief.

The name comes from ‘endogenous’ meaning from within and ‘morphine’ the opiate pain reliever.

Endorphins are neurochemicals made by the central nervous system and the pituitary gland. Because they act on the opiate sensors in the brain they boost pleasure and reduce pain. They are released in times of pain and stress but also during and after exercise.

They are boosted during childbirth to help the birthing process.

Vigorous physical activity like jogging is known to produce a ‘runners high’ but it also acts to relieve stress and is one of the reasons exercise is so good for us.

Endorphins are thought to help boost self esteem, help alleviate depression and reduce anxiety.

Regarding weight loss endorphins are thought to be released when we eat good food and also play a part in appetite control.