Losing Weight For No Reason? Here’s Why.

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Let me guess – you found this page when looking for an explanation as to why you are losing weight for no reason.

There are many of us who wish to lose weight. We would like to slim and trim and fairly fit.

Voluntary weight loss through a strict diet and exercise plan is always rewarding. The feeling we get when we have dropped that weight through efforts of our own is always one of elation.

However, when we begin to lose weight for now reason, that’s when it starts to get worrying.

In my practice, I have encountered a large number of patients who have lost weight but cannot explain why. They feel perfectly healthy as well at the same time.

Some consider it a boon, but the likelihood is that there is a reason for the weight loss.

And this needs looking into.

Before I discuss why you might be experiencing unexplained weight loss, here is a brief look at the types of weight loss.

Types Of Weight Loss

There is no clear definition on types of weight loss. What I am about to discuss with you is what we (as doctors) see in practice.

Broadly classified, there are 2 kinds of weight loss – healthy and unhealthy.

Healthy weight loss is where you only lose excess body fat. The muscles in your body remain fit and fine.

Unhealthy weight loss is where you lose both muscle mass and fat.

Health weight loss is achieved through a healthy diet that is combined with an exercise program. The exercise keeps the muscles fit and helps burn fat. The fat that is burned is what provides energy for your workout.

In unhealthy weight loss, the muscles and the fat content reduce remarkably. The problem with this sort of weight loss is that is accompanied by fatigue and listlessness.

Unhealthy weight loss can be due to crash dieting, an illness such as diarrhea and vomiting or through missing meals. Stress is another cause of unintentional weight loss.

Certain medical conditions can also cause unhealthy weight loss. If left untreated, they can drastically affect a person’s quality of life.

How Much Unexplained Weight Loss Is Worrying?

So losing weight is all well and good, but when should you worry about how much weight you are losing?

It is advised generally that a 5% decrease in body weight over a period of 6 to 12 months is of concern. This is when you have made no attempt to lose weight.

Say for example you are 80 kg in weight. If you do not exercise and fail to follow a health diet, then it is unlikely that you will lose weight.

If one day you notice that your weight has been decreasing gradually, then alarms bells should ring. If you are suddenly around 75 kg, then make an appointment with your doctor.

Losing Weight For No Reason – Causes

When you begin to drop your body weight and you cannot explain it, then make sure you get checked out.

Here are some reasons why you might be losing weight for no reason.

1. Thyroid Disease

The thyroid gland is a small gland that is located in the neck. It is responsible for releasing a hormone thyroxine. This hormone has a number of beneficial effects on the body and is essential for human life.

Sometimes, the thyroid gland can start to produce excessive amounts of thyroid hormone. This is called hyperthyroidism.

The increasing quantities of the hormone can cause muscle and fat breakdown, leading to unhealthy weight loss.

It is simple to make a diagnosis of an overactive thyroid gland. A blood test is all it takes. Clinical examination by a doctor is also essential as this condition can affect the heart, eyes, skin and hands as well.

Once a blood test confirms hyperthyroidism, medical therapy in the form of tablets or radioactive iodine may be prescribed.

Over a period of time, the weight will begin to increase.

2. Diabetes Mellitus

Diabetes affects over 70 million people in India, and is a common cause of unexplained weight loss.


In diabetes, the blood contains excessive glucose that fails to provide energy and nourishment to muscles and vital organs.

Due to this, the muscles become smaller and the body weight starts to reduce.

People with new onset diabetes may not even experience any symptoms. Tiredness and weight loss tend to be more common, but are absent most of the time.

If you are shedding weight and don’t know why, get a blood sugar check done. You may have type 2 diabetes.

Just of note, your chances of developing diabetes is greater if you have a family history of it.

The irony of diabetes is that it can lead to weight loss when the blood sugars are high. However, to manage it effectively, you must lose weight as well.

Once you have been diagnosed with diabetes, make sure you follow the advice you are given by your doctor. This will include dietary advice and exercise programs.

3. Depression

There is a great deal of stigma attached to depression. However, I feel that those who beat it through a positive mental attitude are some of the strongest people emotionally.

losing weight for no reason

Depression can be due to a number of reasons. Reactive depression may be due to the loss of a loved one or due to an unsolvable financial situation.

Depression can also be organic, where no reason for it is identified.

Interestingly, depression can be accompanied by either an increase in appetite (more common) or a loss of appetite. The latter leads to weight loss.

Depression can be a part of a spectrum of other conditions. For example, anorexia nervosa is an eating disorder that is usually accompanied by low mood.

The good news is that depression can be treated and even cured. There is no shame in seeking psychiatric help.

4. Cancer

Cancer is a well recognised cause of weight loss. In fact, if you are losing weight for no reason, then your doctor will likely investigate you for possible cancer.

unexplained weight loss

Cancer can affect almost any part of the body, though the common ones that are seen are prostate cancer (men) and breast cancer (women).

Accompanying symptoms can indicate the site of the cancer. For example, those passing blood in the stools could have colon cancer, while those coughing up blood may have lung cancer. Those who chew tobacco could develop tongue or throat cancer.

The problem with cancer is that it uses up all the nutrients and energy resources to thrive and grow. The rest of the body does not get the nourishment it needs. It beings to wither away while the cancer increases in size.

This leads to weight loss.

Cancer is important to pick up early. The earlier it is caught, the better is the outcome.

Screening tests are now recommended to monitor for the development of cancer. For example, breast cancer screening involves a mammogram and an ultrasound scan. Cervical cancer involves a Pap smear test.

5. Alcohol Abuse

Alcohol in moderation is not a bad thing, but too much of it could harm your health.

can alcohol prevent stroke

Alcohol addicts begin to enjoy only alcohol as a source of food, and completely ignore eating healthier foods as a part of their daily diet.

This means that they have poorer nutrition and this can lead to loss of muscle mass and body fat.

Over a period of time, this can lead to significant weight loss.

Alcohol abusers are often deficient in vitamins and proteins. Liver failure which takes place due to alcohol toxicity often needs intravenous infusion of vitamins

Once alcohol is stopped and a healthy diet is followed, the individual will begin to gain weight again.

6. Infections

Certain infections that persist for long periods of time can lead to loss of weight for no reason.

vital signs fever

For example, worms in the colon (parasitic infections) can feed on all the nutrients we consume in our daily diet. This leaves nothing for the body to use.

This can lead to muscles getting smaller and weight loss.

Other infections such as diarrhoeal illnesses are also causes of unexplained weight loss. Investigating long standing loose stools is a laborious process and requires many investigations including colonoscopies and CT scans.

One well recognised cause of weight loss in India and some other parts of the world is tuberculosis, or TB. While it can affect any part of the body, TB often affects the lungs.

In TB, the bacteria begin to eat up all the nutrients in the body. The condition is accompanied by low grade fever and weight loss. Additional symptoms may also be seen.

Investigating TB is a laborious process, and treatment duration can last up to a year sometimes.


This condition is well known to us all. While it was previously incurable, newer treatments are now available that can slow down progression and improve long term survival.

why am i losing weight

The problem with this condition is that it leads to lowering of immunity. When immunity drops, there is a greater chance of developing infections that can eat away at your energy and make you lose weight.

AIDS, or Acquired Immuno-Deficiency Syndrome is caused by the Human Immunodeficiency Virus, or HIV. The virus has the property of changing the way it affects people, making it a hard one to treat with tablets.

While the presence of the virus itself is of no concern, the health problems that it brings with it are significant. The bottomline is that the virus attacks immune cells called CD4 cells, reducing their levels in the blood stream.

CD4 immune cells are the body’s soldiers. Low CD4 cells counts mean the body has no ability to fight infections.

Over time, the constant infections can lead to weight loss. Infections include tuberculosis, pneumocystitis infections of the lung, Kaposi sarcoma and many others.

If you are losing weight for no reason, chances are your doctor will get a HIV test done to rule out AIDS.

8. Dementia

Dementia refers to memory loss.

As you lose your memory, there is a chance you will lose some weight as well. In the medical world, this weight loss is called cachexia.

A loss of around 5% of body weight in someone with memory loss is significant. This may be accompanied by loss in appetite as well.

The weight loss may be that of lowering body fat or reducing size of muscles.

People with dementia who are losing weight need constant encouragement to eat. Increasing the carbohydrate and protein intake can help keep muscles and bones healthy.


Here is a quick review of what you have just read.

Closing Remarks

There are a number of reasons why you might be losing weight for no reason at all. If you do notice a change in your weight which you cannot explain, make sure you see your doctor about getting yourself investigated.

Dr Vivek Baliga B
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1 thought on “Losing Weight For No Reason? Here’s Why.”

  1. THANKS FOR ALL THE WRITE UP ABOVE . YES I am losing wieght more than 5% year I do not knowwhy. I am 85 years old . Is this because of age??
    Am from Banaglore also.

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