Weight loss in Parkinson's is common, but it's usually mild or, at most, moderate. Changes can occur at any time with Parkinson's disease (PD), but may be more likely in later phases. It's important to recognize and address weight loss because it could lead to malnutrition or exacerbate motor and non-motor symptoms.

Weight Loss Has Many Possible Causes
It can be hard to pinpoint the exact reason your weight is dropping. You could need more calories than you realize. Some motor symptoms, such as rigidity and tremor, can increase your body's energy requirements. Dyskinesia (involuntary movements that can occur with long-term levodopa use) does the same. Motor symptoms also can make meal preparation or dining more challenging.

Non-motor symptoms can sometimes cause a person to eat less:

• Smell loss or depression can lead to loss of appetite and decreased food intake; 
• Constipation and slowed stomach emptying may cause nausea, abdominal bloating or a full feeling after consuming small amounts; and 
• Swallowing problems might require a change in diet or make mealtimes difficult. 

Conditions other than Parkinson's also can bring weight loss. If you can't reach a stable weight despite addressing PD symptoms, consider other possibilities, such as overactive thyroid or, in some situations, cancer. It's often a good idea to have a thorough evaluation by your general medical doctor.

Work with Your Doctor to Manage Weight Loss
Significant weight loss in PD is associated with a lower quality of life. This is because it can make it harder to control motor and non-motor symptoms, and increase risk of infection and bone loss (osteoporosis).

If you notice a shift in your weight, make sure you talk with your doctor. He or she can monitor your weight and together you can work to figure out the reason(s). Your physician may start by asking about changes in mood or eating habits, as well as difficulty with swallowing or constipation. There's no one-size-fits-all approach to manage weight loss, but a few tactics you might consider:

• Adjust Parkinson's medications: Especially if dyskinesia is significant and thought to be a main contributing factor, your drug regimen may be tweaked.
• Treat non-motor symptoms: If depression is decreasing appetite, your doctor may prescribe a medication to help boost mood. For swallowing problems, you may be referred to a speech therapist who can do a detailed evaluation and make appropriate diet recommendations.
• Evaluate other conditions: Sometimes doctors look for other reasons for weight loss. They may draw blood to look at vitamin levels or thyroid function, or they might ask you to see your primary care physician for a full evaluation.
• See a registered dietitian: In some cases, your doctor may refer you for a consultation with one of these experts, who can look at your current diet and help you optimize your calorie, protein and nutritional intake. 

As with every symptom that may accompany PD, weight loss doesn't occur in everyone. And, when it does, it happens to different degrees (i.e., mild in some and more significant in others). Management of weight loss is individualized and targeted to the underlying cause.

Read about diet and Parkinson's on our webpage and "Ask the MD" blog.