Multiple sclerosis (MS) can make it harder to stay at your usual weight. Some people gain weight, and others lose weight. For some people, unexplained weight loss can be an early warning sign of MS and may continue over time.

“Does anyone have issues keeping weight on?” asked a member of MyMSTeam. “My diet is becoming more limited over time, and now I keep losing weight.”

Here, we’ll cover possible causes of weight loss with MS and tips that may help.

🗳️ Has your weight changed since you were diagnosed with MS?

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How Common Is Weight Loss in MS?

Many people living with MS notice changes in their weight. Weight gain is more common than weight loss.

Relapsing-remitting multiple sclerosis (RRMS) is a type of MS marked by periods of new or worse symptoms followed by times of recovery. More than half of people with RRMS may live with a higher body weight, which can make weight management an important part of care for some people.

In one study, 20 percent of people with MS were malnourished, and 80 percent were at risk of malnutrition. In this study, nearly half of the participants had a high body mass index (BMI), and only about 6.6 percent were underweight.

People in the study with a low body fat percentage and those with significant weight loss in the past six months were at the highest risk of malnutrition. Note that people of any weight can be malnourished.

Tell your doctor if you’re losing weight without trying or if you’ve lost significant weight in a short time.

Why Is Unintended Weight Loss a Problem?

Weight loss can be a concern when it happens without trying. According to Can Do Multiple Sclerosis, unintended weight loss can contribute to malnutrition and frailty in people with MS.

Frailty

Without the proper treatment, losing weight without trying or being underweight can contribute to physical frailty. Physical frailty means your body may have a harder time recovering from illness or injury.

Frailty can also involve weakness, fatigue, and exhaustion. One MyMSTeam member described this alongside their weight loss, saying, “I'm losing weight, not trying to. In the last month, I’ve gone from 125 pounds to 104. Nothing fits. I'm exhausted. I even wake up tired.”

Malnutrition

Malnutrition can also be linked to unintended weight loss. Malnutrition happens when your body doesn’t get or use the nutrients it needs. Over time, this can affect how your body works.

A weakened immune system can put you at risk of illnesses, and organs like your heart and gastrointestinal (GI) system can have a harder time doing their jobs.

Causes of Weight Loss in MS

Weight loss in MS isn’t always linked to just one cause. You might unintentionally lose weight because of MS symptoms, treatments, or complications.

Low Appetite

Some people with MS have trouble maintaining their appetite. Stress, depression, or anxiety can lower your appetite when you’re living with MS. You might have a loss of appetite because of MS fatigue, pain, and other symptoms during a relapse.

MyMSTeam members have described losing their appetites with MS. “I’ve always been physically fit, lots of muscle, but thin,” said one member. “I don’t work out now. I lost all my muscles, and I’m too thin. My appetite has shrunk.”

Another member mentioned losing their appetite because of MS symptoms affecting their tongue: “I’ve had a burning tongue and no appetite.”

Swallowing Problems

Difficulty swallowing, a common MS symptom, can make it hard to eat enough food even if your appetite is normal. “My swallowing problems are causing a lot of weight loss and anxiety around eating and taking medications,” said a MyMSTeam member.

Gastrointestinal Distress

Some people with MS may have GI problems when MS affects the nerves that help control digestion. Symptoms like nausea, vomiting, and diarrhea can make it harder for your body to get nutrients from food. Over time, this can contribute to weight loss and make it harder to stay at a healthy weight.

Inflammation

Weight loss in MS has been linked to increased inflammation in the body. Some people with MS have high levels of inflammation in their bodies, which may be linked to unintentional weight loss. When this inflammation was treated in research studies, the weight loss slowed down.

Medication Side Effects

Several MyMSTeam members have reported weight loss from side effects of disease-modifying treatments for MS. Side effects like diarrhea, indigestion, and nausea can reduce your appetite or make it harder to eat.

Members wrote:

• “Anyone experience weight loss when using interferon beta-1a (Rebif)?”
• “I also lost a lot of weight. I’m on teriflunomide (Aubagio) but stopped after four months. So far, I haven't gained it back.”
• “Been on dimethyl fumarate (Tecfidera) two months now. Has anyone else had a loss of appetite and weight loss? Had the other GI side effects and the flushing, but didn’t expect to lose weight or interest in food.”

How To Manage Weight Loss in MS

If you’re losing weight without trying, talk to your MS specialist. They can help you figure out what may be causing it. They can suggest ways to slow weight loss or help you gain weight, if needed. Along with treating your MS, the following strategies may help with unwanted weight loss.

Extra Protein

Adding more protein to your diet can help increase your calorie intake. Protein shakes might be easier than solid foods if you have trouble chewing.

MyMSTeam members who have lost weight without trying have shared tips for adding more protein to their diets:

• “I started Ensure protein drinks. I’ve finally regained my appetite and am eating better. So far, so good, no more weight loss.”
• “Protein powders have helped me gain some weight and keep it steady.”

Talk with your doctor or a registered dietitian before adding protein drinks or powders to your routine.

Healthy Fats and Other Nutrient-Dense Foods

You may also benefit from eating more high-fat and nutrient-dense foods, including healthy fat sources like avocados, nut butters, and cheese.

“I struggle with keeping weight on often. I do find eating peanut butter by the tablespoon and an avocado a day helps a little,” said a MyMSTeam member.

Muscle-Building Exercise

A MyMSTeam member went online looking for tips on maintaining muscle mass and body weight. “I’m losing weight. I’m losing muscle. What can I do?” they asked. Another member recommended, “Weight-bearing exercises to keep and build muscles.”

Some types of physical activity can help you build muscle and maintain a healthy weight. Choose activities that fit your abilities. If you’re living with disabilities from MS, a physical therapist can help you find exercises that fit your needs.

Medication Adjustments

Managing your MS can help reduce symptoms like pain or swallowing difficulties that affect your eating habits. If medication side effects are lowering your appetite, your doctor may be able to adjust your dose or suggest changes to your treatment plan.

When To See a Doctor for MS Weight Loss

You should tell your doctor if you’re losing weight without trying. If the number on the scale is going down even though your diet or exercise habits haven’t changed, MS symptoms, inflammation, or medications may be playing a role.

Unintentional weight loss can also happen for reasons other than MS. Tell your doctor so you can work together to find out what’s causing it. They may want to check for thyroid problems, heart disease, or cancer. Your doctor may refer you to a nutritionist or dietitian who can support you in maintaining a healthy weight.

Join the Conversation

On MyMSTeam, people share their experiences with multiple sclerosis, get advice, and find support from others who understand.

What steps have you taken to manage weight loss in MS? Let others know in the comments below.