Common Reasons for Weight Loss and Muscle Wasting

Weight loss and muscle loss may be caused by lack of exercise and a poor diet, which can often be reversed. However, it may also be a symptom of a serious, potentially life-threatening medical condition.

Muscle atrophy may be caused by not getting enough physical activity. This condition can be addressed with a diet and exercise program. Whether or not you lose weight in addition to losing muscle is largely dependent on your diet.

Lack of activity may have several causes, including:

• A sedentary job and lifestyle
• Bed rest due to illness or injury
• Inability to move the limbs due to brain or nerve damage

Muscle loss after 30 is also a normal part of aging. This type of muscle atrophy is called sarcopenia. Most times, it's due to the hormonal changes that occur with age, including decreased testosterone.

Every decade, you may lose as much as 3 to 5 percent of your total muscle mass, states Harvard Medical School. Decreased muscle mass results in increased weakness and stability and may put you at greater risk for falls and injuries.

​Read more:​ How to Build Up Atrophied Muscles

Fortunately, you can slow or prevent muscle loss due to aging with diet and exercise. Make sure you get enough protein in your diet to maintain and build muscle.

Do resistance training workouts for all major muscle groups at least two to three times per week. Muscles can adapt to a workout, which is why it's recommended to gradually increase the intensity of your training and include different exercises in your workout.

Fat loss and muscle loss may be a sign of the eating disorder called anorexia nervosa. It occurs when an individual limits his food intake to dangerously low levels. In many cases, people with anorexia have a distorted body image and believe that they're overweight when they are not, according to the Office on Women's Health.

In addition to limiting food intake, people with anorexia may also take laxatives and exercise excessively in an attempt to control their weight. Other symptoms of anorexia include:

• Brittle hair and nails
• Feeling cold
• Dizziness
• Lack of energy
• Irregular period or not getting a period at all
• Confusion
• Poor memory

​Read more:​ Signs & Symptoms of Starvation Mode

Another potential cause of muscle wasting is food malabsorption. In this case, even if an individual is eating a healthy diet with enough calories, the nutrients are not properly absorbed in the digestive system. Other symptoms of malabsorption may include:

• Weakness
• Difficulty thinking clearly
• Changes to the stool
• Bloating and gas

Malabsorption has many potential causes, notes Medline Plus, including Celiac disease, Crohn's disease, worms or a parasitic infection, Whipple disease, overgrowth of bacteria in the intestine and cystic fibrosis. Some medications, such as tetracycline and certain antacids, may also interfere with the absorption of nutrients.

Muscular dystrophy is a genetic condition that causes progressive muscle weakness and atrophy. It may progress quickly, causing sudden loss of muscle mass, but its symptoms can also develop at a slower pace. Muscular dystrophy is either inherited or results from a sudden gene mutation.

There are several types of muscular dystrophy. For example, Duchenne muscular dystrophy is a rapidly progressing form of the disease that typically affects boys between the ages of three and six, points out Cedars-Sinai. In this form of the disease, the mutated gene affects the protein called dystrophin that holds muscle fibers together.

Another type, Becker muscular dystrophy, affects both genders with symptoms appearing in their teens and early 20s. Facioscapulohumeral muscular dystrophy primarily affects the muscles in the face, arms and shoulders. The specific mutation varies and is not known for every type of muscular dystrophy.

Other symptoms of muscular dystrophy include:

• Difficulty breathing or swallowing
• Enlarged calf muscles
• Difficulty climbing stairs or getting up from a seated or lying position
• Enlarged heart
• Stiffening of the limbs

While there is no cure for the disease, doctors can help treat its symptoms and slow its progression. Treatment options include physical therapy and medications, such as corticosteroids.

Muscles contract when they receive the signal from nerves. If these nerves are damaged, it may result in muscle weakness and atrophy. Nerve or muscle damage may occur from an injury. Depending on the nerves affected, symptoms may affect the entire body or just one body part.

Another cause of muscle loss is a neuromuscular disease, such as amyotrophic lateral sclerosis, which is also called ALS or Lou Gehrig's disease. Neuromuscular disorders may be genetically inherited or the result of a gene mutation. Some conditions, such as multiple sclerosis, are caused by disorders of the immune system. Both ALS and multiple sclerosis affect the central nervous system.

Symptoms of neuromuscular diseases may include:

• Muscle wasting
• Problems with movement and balance
• Cramps, pain and twitching of the muscles
• Numbness and tingling
• Droopy eyelids
• Difficulty breathing or swallowing

Currently, these diseases cannot be cured. However, a doctor may be able to treat and slow the progression of symptoms.

Approximately half of all patients with cancer will exeperience weight loss and cachexia, or progressive loss of muscle mass, states Ohio State University. In advanced-stage cancer, the number of patients affected increases to 80 percent. Cachexia causes death in approximately 20 to 40 percent of all people with cancer.

Other symptoms of cancer cachexia include:

• Physical deterioration
• Weight loss
• Physical weakness
• Mental fatigue
• Poor quality of life

The cause of cachexia in people with cancer is still being explored, but it is believed that the cancerous tumor releases certain molecules that cause the patient to lose his appetite and decreases nutrient absorption. The body then consumes fat and muscle to get the nutrients it can no longer absorb from food.

Cachexia is not isolated to people with cancer. The condition is also seen in those with chronic kidney disease, HIV and AIDS, congestive heart failure and chronic obstructive pulmonary disease.