5 Hormones and How They Affect Your Body Composition

Hand writing Hormones with marker to emphasize how hormones affect your body composition

It’s not just how much you eat, the quality of what you munch on, and how much you work out, hormones play a role in determining your body composition as well. Of course, what you eat, in turn, impacts hormones, so making smart dietary choices is still key to optimizing your physique for health and fitness. Let’s see what impact 6 key hormones play in influencing your body composition and ability to lose weight.


Insulin is a hormone that unlocks tiny passageways for glucose to enter the cell. Getting glucose into cells promptly is key as high levels of glucose in the bloodstream are damaging to cells and tissues. Plus, glucose needs to travel inside the cell so the cell can use it as an energy source. Insulin is also a fat-storage hormone. When insulin levels are high, such as after a meal, it blocks a cell’s ability to burn fat as an energy source. It also promotes fat storage. People who have high levels of insulin much of the time due to insulin resistance have a hard time losing body fat as insulin blocks the release of stored fat. Healthy insulin and blood glucose levels are the key to metabolic health and glucose control.

How It Impacts Your Body Composition:

High levels of insulin, due to insulin resistance, make it easier to store body fat, particularly around the midsection. People with insulin resistance frequently have excess visceral fat, deep abdominal fat that wraps around the organs in the pelvic cavity. This type of fat is the most dangerous from a health standpoint and is associated with other health problems, like fatty liver. If you have insulin resistance, you’ll likely have a large waistline and a tendency to store fat around the middle and upper back, the so-called “love handle” region.

On the plus side, insulin also helps amino acids from protein get into cells for muscle repair after a workout. Eating a carb and protein snack helps raise insulin short-term to help your muscles start the repair process after exercise. So, insulin does have benefits for your physique as well.


Cortisol is the so-called “stress hormone,” a hormone your body releases when you’re under physical or mental stress. Actually, your adrenal glands release this hormone in a cyclical manner all the time with the level being highest in the morning when you wake up, followed by a gradual decline in the evening. However, physical and mental stress can cause your adrenal glands to pump out excess cortisol. This elevation in cortisol can lead to high blood pressure, reduced immune function, and, longer term, bone loss, and insulin resistance.

How It Impacts Your Body Composition:

A chronically elevated cortisol level causes a change in where on your body stores fat. Fat storage shifts from the hips and lower body to the midsection. As with insulin, you experience an increase in visceral fat. Plus, a high cortisol level can lead to the breakdown of muscle tissue as well. Ways to keep cortisol under control:

·       Don’t overly restrict calories or carbs

·       When you work out, don’t overtrain

·       Get 7+ hours of sleep nightly

·       Find a way to ease stress, whether it be meditation, yoga, or a hot bath

Growth Hormone

Growth hormone, secreted by the pituitary gland in the brain, plays an important role in growth during childhood and adolescence. Levels of this anabolic hormone decline as we age with growth hormone dropping off significantly during late adulthood. Low levels of growth hormone are linked with depression, fatigue, bone loss, memory changes, as well as elevations in blood triglycerides and blood pressure.

How It Impacts Your Body Composition

Being an anabolic hormone, low growth hormone is associated with loss of muscle tissue and muscle strength. One reason we lose muscle tissue as we age is growth hormone levels drop. Plus, growth hormone is catabolic in the sense that it promotes fat loss, especially around the midsection. People with low growth hormone store more fat around the trunk and abdomen, what we call truncal obesity. This is the least healthy place to store fat.


Estrogen is one of the primary female sex hormones, the other being progesterone. During the reproductive years, estrogen produced by the ovaries helps prepare the lining of the uterus for implantation of a new life, should you decide to reproduce. It’s released in a cyclical fashion and peaks during the midpoint of the menstrual cycle before falling, only to repeat this pattern the next month. After menopause, estrogen production by the ovaries dramatically decreases. That’s when some women notice a change in body composition.

How It Impacts Your Body Composition

During the years you’re capable of reproducing and you have an abundance of estrogen, you tend to store fat around the hips and thighs. As estrogen falls after menopause, fat storage tends to shift from the thighs and hips to the midsection. It’s not hard to see why waistlines become thicker after menopause as a variety of factors come into play – a drop in estrogen and growth hormone and, sometimes, an increase in cortisol. Plus, insulin resistance can become a problem after menopause as well.

Thyroid Hormone

Thyroid hormone is the master regulator of your resting metabolic rate. It controls your metabolism by altering body temperature, appetite, and the activity of enzymes. Your thyroid produces two thyroid hormones, T3 and T4 under the direction of the hypothalamus and pituitary gland in your brain. T3 is the active form. Your liver and kidneys convert inactive T3 to active T4.

How It Impacts Your Body Composition

If your thyroid gland is under-active, you’ll feel sluggish and will likely gain weight, sometimes significant amounts of body weight. Women are more susceptible to a sluggish thyroid and the most common cause is autoimmune, a condition called Hashimoto’s thyroiditis. If you are having problems losing weight, it’s a good idea to check your thyroid function via a blood test to be sure it’s not working against you.

Another way your thyroid can slow is if you restrict calories too much. To help you avoid starvation, your thyroid slows your resting metabolic rate, meaning your body no longer burns as many of the calories that you take in. That’s why it’s better to focus on diet quality rather than drastically cutting back on calories when you’re trying to lose weight.

The Bottom Line

Now, you have a better idea of the hormones that impact your ability to lose weight and how to keep them from misbehaving. Lifestyle matters!



Indian J Endocrinol Metab. 2011 Sep; 15(Suppl3): S197–S202. doi: 10.4103/2230-8210.84865
Science Daily. “Estrogen’s effects on fat depends on where it’s located”
Harrison’s Principles of Internal Medicine. 19th edition.


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