How Do Hormones Influence a Person's Weight?

There are many factors that contribute to a person's weight. Some are related to lifestyle. Others are unseen and related to our individual biology. Hormones that regulate how much body fat we store are one of those unseen factors. The specific hormones that play important roles in determining a person's weight, and often work in relation to other hormones include leptin, ghrelin, GLP1, GIP and other fullness hormones, insulin, glucagon, cortisol, and thyroid hormones.

Leptin

Leptin is produced in body fat. It is a hormone that tells our brain how much body fat we have and helps keep our weight steady and in normal range. When we gain weight, our leptin level goes up. This reduces our appetite and promotes energy expenditure to cause weight loss bringing us to our previous weight. If we lose weight, our leptin level goes down and, likewise, we eat more food and our metabolism slows. A common problem in obesity is “Leptin Resistance”, where the leptin level is high but it is not causing weight loss as it should. When this happens, you maintain the new higher weight rather than return to your previous lower weight. 

Amylin

Amylin is a hormone produced in the pancreas and decreases food intake. In experiments it has been shown to reduce Leptin Resistance and cause weight loss. It is used in the treatment of diabetes for lowering sugar but can have a role in weight loss management.

Ghrelin

Ghrelin is produced in the stomach. It is our hunger hormone and therefore essential for our survival as it drives us to eat. When we skip a meal our ghrelin level becomes very high so that we eat more food at the next meal and can sometimes overeat. What we eat also affects ghrelin. Carbohydrate is the most effective macronutrient to lower our ghrelin level. Protein is less effective but works to keep ghrelin suppressed for longer. An ideal meal contains both carbohydrate and protein taking advantage of both these macronutrients’ ability to lower ghrelin quickly, effectively and for as long as possible.

Glucagon-Like Peptide 1 (GLP1) and other Fullness Hormones

GLP1 is one of several “nutrient sensing” fullness hormones produced in the intestine when we eat. It makes us feel full and satisfied so that we stop eating. It is also important for managing our sugar levels. When our sugar level rises after eating, GLP1 brings it down. Individuals vary in how much hormone they produce, making it easy or more difficult to determine fullness and satisfaction. When ghrelin is high, we produce less GLP1, making us eat more food. Manufactured GLP1 hormone is used in the long-term treatment of obesity, helping patients sense fullness and satisfaction more easily.

Gastro Inhibitory Peptide (GIP)

GIP is another nutrient sensing fullness hormone and is also used in combination with GLP1 for the treatment of obesity.

Glucagon

Glucagon is produced in the pancreas when we have a low sugar level a few hours after eating. It helps bring our sugar level back to normal by making the liver release stored sugar to our body. This allows us to have more time between meals so that we don’t have to eat all the time. Glucagon also suppresses our appetite and increases our metabolism, favoring weight loss. It is being studied in combination with GLP1 as a newer weight loss treatment.

Insulin

Insulin is the principal hormone that regulates our blood sugar levels and is also released by the pancreas. This hormone delivers sugar to all our organs for normal health. Insulin can influence hunger and fullness. High insulin levels can cause, and be caused by, obesity leading to weight gain. However, insulin interacts with many other hormones and can have different effects, including loss of appetite, depending on these interactions.  

Cortisol

Known as the "stress hormone," cortisol is produced by the adrenal glands (which also produce adrenaline) in response to stress. When we experience chronic stress, higher cortisol levels can cause an increased appetite leading to weight gain especially around the abdomen.

Thyroid hormones

The thyroid gland produces hormones that regulate metabolism. Certain thyroid conditions can impair the thyroid's production of these hormones, which can lead to either weight gain or weight loss. Treatment of an overactive thyroid generally causes weight gain, however treatment of an underactive thyroid has not been shown to cause weight loss. So, although thyroid hormone has an important role in our metabolism it does not seem to be helpful for weight loss.

How hormones and weight loss or gain are connected

Body fat regulation is complicated. Many hormones work together to make sure that we eat what the body needs to survive, that we have a reasonable amount of fat storage in reserve, and they work to prevent our weight from swinging from one extreme to another. 

There are lifestyle changes that can improve the balance of these hormones. Health focused lifestyle choices, such as eating more fiber and less processed foods, eating three times a day, increasing our muscle health with physical activity, improving the timing and quantity of sleep and learning stress relieving activities can optimize each of these hormone levels. This approach helps prevent weight gain and can cause small amounts of weight loss if sustained. 

Lifestyle choices for balanced hormones and a healthy weight

Most of us can balance our hormones through healthy lifestyle choices, including:

• Eating three to four balanced meals a day that include fruits, vegetables, lean proteins, and healthy fats. All of these foods will prevent high ghrelin levels, keep ghrelin suppressed for longer, increase GLP1, and stabilize sugar levels and lower insulin.
• Eating less processed foods will lower ghrelin.
• Consistently exercising, ideally 30 minutes five times a week, will improve insulin sensitivity and reduce cortisol levels.
• Establishing a consistent, quality sleep routine. Going to bed at about 10 p.m. can increase leptin levels. Adequate sleep helps reduce cortisol and improve insulin sensitivity
• Cultivating a "toolbox" of stress management resources, such as meditation, yoga, or mindfulness will lower your cortisol. 

Understanding how hormones play a part in achieving and maintaining a healthy weight is only part of the picture. For best results, focus on the lifestyle changes you can make to improve your overall health, including your weight. If you're struggling to identify a plan you can maintain on your own, the providers at our Obesity Medicine program can help.