When someone has a thyroid that is stressed or not functioning properly, it will lead to weight changes that are very hard to regulate with food and even when exercising.  

Hypothyroidism

Hypothyroidism is when your thyroid isn't working fast enough.  This means your metabolism slows down and your body burns less calories often leading to weight gain. You may be eating the same amount of food you had in the past but gain weight and not understand why.

When your thyroid is overworking, it is sending out too many hormones, this is called hyperthyroidism. Now your body is metabolizing way more calories and constantly working which will have you lose weight.

Of course your body is very complex and it is not as easy as only regulating your thyroid since your thyroid helps with function of many other organs. Heart rate, breathing, energy levels, temperature, digestion are all effected by the thyroid gland.  Basically the thyroid sends its hormones into the blood which flows throughout the whole body and sends messages to other cells.  

How does the thyroid effect metabolism?

Your metabolism involves a series of processes that break down food and convert it into the energy your body needs to run. So basically, it helps with our body energy processing.

What are Thyroid Hormones?

Your thyroid works closely with your hypothalamus and pituitary gland in your brain that regulate hormones. The thyroid sends off three hormones T4, T3 and calcitonin. Lets start with T3 and T4.

T3 has 3 iodine molecules
T4 has 4 iodine molecules

Iodine is absorbed into our bloodstream by foods we eat and then carried to the thyroid for processing. The pituitary gland analyzes the levels of iodine and tells the thyroid how much to release into the blood stream.

Calcitonin regulates Calcium and Phosphate in the blood. Phosphate helps in building and repair of bones and teeth and Calcium helps bones and teeth keep their structure and firmness. Calcium is key for signals from the nerves to the muscles or movement and communication of the brain and body.

The Thyroid works along with a number of other hormones, proteins, receptors, molecules. It is a very complex gland.

What else can cause weight gain?

1. Leptin resistance: 

Leptin is a hormone released by your fat cells. I maintains energy balance and metabolism but also tells your hypothalamus when you've had enough to eat and when your body should burn fat.

When there's too much leptin (which also happens when you're obese), your body becomes less sensitive to leptin's signals. This is leptin resistance. 

This means that your hypothalamus is not receiving messages indicating that you are satiated. Now, your body goes into starvation mode, decreasing the number of calories you are burning in your body.

During this time, your thyroid slows down your metabolism. Your appetite increases, you eat more, and you burn fewer and fewer calories, all resulting in weight gain.

Now, the more weight you put on, the more leptin your fat cells make, creating a domino effect.

2. Insulin Resistance:

Insulin is a hormone that's produced by your pancreas and keeps your blood sugar levels regulated.

It works by telling your cells to absorb the excess sugar, or glucose, in your blood after you eat and use it for energy.

Just like in leptin resistance, when your insulin levels are continually elevated, your cells become less sensitive to the signals insulin gives.

This results in needing even more insulin to keep your blood sugar level steady. Having higher levels of insulin causes weight gain and raises your risk of developing type 2 diabetes. It basically wears down your pancreas from overworking.

Insulin is considered a fat-building hormone. It increases the amount of fat around the abdominal organs, which is highly inflammatory and can raise your risk of chronic diseases like type 2 diabetes, heart issues, blood circulation decrease and wear and tear on other organs and tissues.

Hormones and metabolism are very complicated. If you have an under active thyroid, you may have to work harder to lose weight than someone without a thyroid disorder.

Getting this gland to normalize is crucial to maintaining weight, hormone balance, organ health.  Amino Neuro Therapy and chiropractic can help regulate your body's systems without drugs or surgery.

References:

https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284