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10 Underlying Causes of Chronic Fatigue and Weight Gain

Fatigue and weight gain are not severe conditions, as they can happen to anyone due to their busy routine and poor eating habits. No wonder, overworking, lack of sleep, poor eating habits can cause fatigue and weight gain in a person. Yet, a person might still experience fatigue and weight loss even if they’re not experiencing any of the preceding causes. There may be some underlying reasons for this.

So, why do we experience chronic fatigue and weight gain?

Several reasons can cause chronic fatigue and weight gain, including lack of essential nutrients in the diet, congestive heart failure, viral or bacterial infection, chronic fatigue syndrome, medication, hypothyroidism, insomnia, polycystic ovary syndrome, depression, crushing disease, and menopause.

Let me disclose each individually, read on.

Table of Content

Chronic Fatigue and Weight Gain Underlying Reasons

Getting tired from a hectic daily routine will cause no one to pay attention. Nowadays, it is normal for everyone to overwork to meet our society’s daily demands. In the haste of a hectic schedule, one may neglect his diet, leading to weight gain

But what if a person doesn’t overwork and takes proper care of his diet, but still faces chronic fatigue and weight gain. As you know, fatigue and weight gain are the most common symptoms of several diseases. 

Chronic Fatigue and Weight Gain

Many underlying conditions can lead to unexplained weight gain and fatigue.

Chronic Fatigue Syndrome

A person with chronic fatigue syndrome will experience fatigue lasting up to six months. But the question is, what causes chronic fatigue syndrome? It is caused by many factors, including hormonal imbalance, viral infection, mental trauma, changes in immunity, etc.

Insufficient sleep, poor eating habits, excessive adrenal hormone release, improper thyroid functioning, and poor gut functioning, are symptoms of chronic fatigue syndrome.

Nevertheless, major symptoms of chronic fatigue syndrome that can lead to weight gain are listed below:

Insufficient Sleep

Sleep disturbances caused by chronic fatigue cause people to awaken during the night. Proper sleep helps a person reduce insulin sensitivity, preventing fat accumulation in the body. Recent studies show that sleep deprivation results in lowering a hormone named leptin in the body, which is responsible for reducing appetite. It also changes the hormonal level of ghrelin.

This hormone produces the sensation of hunger in the body, and sleep inadequacy causes an increase in ghrelin hormone. Due to the low amount of leptin and high amount of ghrelin, a person never feels complete, and it may lead to overeating, which eventually results in weight gain.

Chronic Fatigue Syndrome

Excessive Cortisol Secretion

Continuous fatigue and stress in CFS affect the adrenal secretion of cortisol. High amounts of cortisol in the blood increase insulin resistance in the body. As a result, insulin insensitivity prevents glucose from being broken down and used, resulting in a fat buildup in the body.

Improper Thyroid Functioning

A thyroid gland that produces hormones that control the rate of your metabolism may adversely influence weight control. Hypothyroidism caused by CFS can result in weight gain due to imbalanced metabolic activities.

Imbalance Diet

During CFS, our body is always in need of energy. To meet this need, one might eat an improper diet, leading to overeating. It can also lead to weight gain.

Treatment For Chronic Fatigue Syndrome 

Treatment of chronic fatigue syndrome is not apparent, although it can be relieved by curing the most disturbing symptoms. Depression is the most common symptom of CFS, so antidepressants can be taken. This will help a person to get proper sleep and avoid fatigue. 

Ibuprofen, naproxen sodium, fibromyalgia, including pregabalin, gabapentin, duloxetine, etc., can be prescribed by your doctor to treat pain caused by CFS. Besides these drugs, blood pressure controlling medications are often recommended.

In some cases, a person suffering from CFS who does not wish to take medications may take counseling, which can be very helpful. Your counselor will suggest you change some of the things you do every day in this type of therapy.

Polycystic Ovary Syndrome (PCOS)

Females with polycystic ovary syndrome face fertility issues as they enter puberty. But, how PCOS can lead to weight gain and chronic fatigue? As mentioned earlier, PCOS is a hormonal disorder. It increases insulin resistance in the body. 

Consequently, the glucose present in the blood is not converted into energy due to insulin insensitivity. This leads to a high sugar and insulin level in the blood, causing type 2 diabetes. Nearly half of females with PCOS also have type 2 diabetes. 

Higher amounts of insulin in the blood trigger the production of a male hormone named androgen in the female body, leading to obesity. Androgen plays an essential role in the metabolism of visceral fats. Higher androgen levels in the female body affect fatty tissue metabolism, leading to obesity. 

Depression can also occur while suffering from PCOS, which can further cause fatigue in the body.


Insomnia can lead to chronic fatigue, as proper sleep is needed to get relief from daily activities. But how does insomnia affect your body? Insomnia can increase the ghrelin hormone in the body. 

Ghrelin hormone increases the hunger sensation in the body. Hormonal increases cause an increase in appetite, leading to overeating, thus weight gain. Also, the body’s leptin levels can be affected by insomnia. After eating a sufficient diet, the body needs this hormone to feel complete. 


However, a decrease in leptin level does not cause a person to feel complete. As a result, overeating can also occur. Besides this, insomnia can also increase the cortisol level, which can cause weight gain.

Congestive Heart Failure

The condition of congestive heart failure (CHF) affects the heart’s ability to circulate blood throughout the body. As a result of this condition, tissues can become congested due to fluid retention. Mainly this occurs in the lungs. This can result in a sudden 3 to 4 pounds weight gain in a week. When blood does not circulate properly in the body, tissues cannot receive enough oxygen, which can result in routine fatigue.


Several medications can also cause weight gain. For example, antidepressants, steroidal drugs, birth control pills, diabetes medication, and blood pressure control medication are common nowadays. These drugs can lead to weight gain as well as fatigue. 

Cushing Disease

Cushing’s disease is a chronic hormonal disorder caused by the body producing excess cortisol, a stress hormone. The adrenocorticotropic hormone (ACTH) from the pituitary gland is responsible for the release of cortisol. Any tumor in the pituitary gland can disturb the release of cortisol. Body fat can be altered as a result of cortisol impairment. 


Hypothyroidism is an endocrine disorder that affects the release of hormones from the thyroid glands. Particularly, Thyroxine and triiodothyronine are the two main hormones released from the thyroid glands. Both of these hormones affect the basal metabolic rate of the body. Also, these hormones are involved in energy production through the breakdown of glucose. 


Hypothyroidism symptoms include the lack of these hormones, which results in energy deficiency. Thus, glucose cannot break down into ATP, and it accumulates in the form of fat in the body. This can result in weight gain and fatigue. 

The most common cause of hypothyroidism is a lack of iron in the diet, and the condition is also known as myxoedema when hands or feet become puffy. These hormones also work on the pancreas and liver to stimulate the metabolism of stored fat.

Due to hypothyroidism, the liver and pancreas become unable to perform their functions properly. All these factors affect the human normal body activities that result in chronic fatigue and weight gain.


Question: What hormones cause weight gain and sluggishness?

Answer: Cortisol released from the adrenal glands, thyroid hormones, insulin released from the pancreas, and sex hormones including estrogen, progesterone, and testosterone can cause both fatigue and weight gain in an individual.

Question: What foods should I avoid with chronic fatigue syndrome?

Answer: Sugar should not be added to the food of those with chronic fatigue syndrome, and sweet foods such as fruits and vegetables should be eaten. Further, patients with CFS should avoid fried and junk foods. Boiled food can be a healthy option for them.

Question: Can insomnia cause weight gain and fatigue?

Answer: Yes, insomnia can result in both weight gain and fatigue. Insomnia can cause a high level of ghrelin and cortisol and decrease the leptin hormone in the body. Weight gain and fatigue are likely results.

Bottom Line

It can be hard to identify these symptoms, as they are usually mistaken for something else. Getting an accurate diagnosis is essential in order to have effective treatment options. Chronic fatigue does not have a cure, but taking preventative measures like getting enough sleep and eating healthy can reduce the symptoms of chronic fatigue and weight gain.

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