Is weight loss a common side effect of Multiple Myeloma treatment?

Yes, weight loss is relatively common in people with multiple myeloma and can be linked to both the cancer itself and its treatments. Multiple myeloma can cause symptoms like nausea, vomiting, and high calcium levels, all of which may reduce appetite and lead to unintentional weight loss. ^[1] Weight loss is also recognized as a common symptom across many cancers, including multiple myeloma. ^[1] In addition, several myeloma drugs can decrease appetite and cause gastrointestinal side effects, which can further contribute to weight loss. [PM14]

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Why weight loss happens

• Cancer-related factors: Multiple myeloma itself can trigger nausea and vomiting, often due to elevated blood calcium, making it hard to maintain regular food intake. ^[1] Weight loss is additionally noted as a frequent symptom in myeloma. ^[1]
• Treatment side effects: Some therapies (for example, selinexor) commonly cause decreased appetite, nausea, vomiting, diarrhea, and fatigue, which can reduce calorie intake and increase losses. [PM14]
• Transplant/High-dose therapy effects: High-dose chemotherapy and autologous stem cell transplant can temporarily worsen nutritional status, with gut inflammation, diarrhea, and reduced appetite leading to short‑term weight loss. [PM15] Supportive strategies that protect the gut can lessen treatment-related diarrhea and weight loss. [PM17]

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Why managing weight matters

Maintaining a stable weight supports energy, healing, and tolerance to treatment. Clinical data suggest that malnutrition in hematologic cancer care is associated with worse outcomes and more healthcare use, highlighting the importance of early nutrition support during intensive therapies. [PM13]

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Practical ways to manage and prevent weight loss

Eat enough calories and protein

• Aim for high-calorie, high-protein foods to maintain weight, rebuild tissues, and support recovery. ^[2] Choosing foods that provide sufficient calories, protein, vitamins, minerals, and fluids is helpful during treatment. ^[3]
• Small, frequent meals can be easier to tolerate than large meals when appetite is low. ^[4]

Improve appetite and reduce nausea

• Structured eating: Try eating by a schedule (for example, every 2–3 hours), rather than waiting for hunger to return. ^[4]
• Flavor tweaks: Slightly sour flavors (like lemon or vinegar in dressings) may stimulate appetite when food seems unappealing. ^[5]
• Medication support: Antiemetics (like 5‑HT3 antagonists) and other agents (e.g., neurokinin‑1 antagonists or olanzapine) can reduce nausea; appetite stimulants may help selected individuals under clinician guidance. [PM14]

Manage diarrhea and gut discomfort

• Antidiarrheals such as loperamide or bismuth subsalicylate can reduce losses from diarrhea. [PM14]
• Protecting the gut during high-dose chemotherapy is an emerging supportive strategy and may reduce diarrhea and weight loss. [PM17]

Build a routine that works for you

• Eat when you feel able and keep intake consistent; if a medication requires food, match mealtimes to dosing. ^[6]
• Snack smart: Easy options like yogurt, nut butter on toast, eggs, smoothies, or fortified soups can pack calories and protein in small portions. ^[4]

Involve nutrition experts early

• Ask for a referral to a registered dietitian for a tailored plan that fits your symptoms, preferences, and treatment schedule. ^[3] If you’re concerned about recent weight changes, seeking dietitian input is encouraged. ^[7]

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Red flags: when to escalate care

• Rapid or ongoing weight loss, inability to keep fluids down, or persistent vomiting/nausea despite medicines should prompt timely medical review to adjust anti‑nausea regimens and consider additional support. [PM14]
• Severe appetite loss with difficulty meeting needs may warrant short‑term nutrition support; your team may discuss options like oral supplements and, in select cases, temporary feeding tubes to stabilize weight until eating improves. ^[8]

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Evidence-based tools and tips

• Scheduled small meals and snacks help counter appetite loss and prevent long gaps without intake. ^[4]
• High‑calorie add‑ins (oil, butter, cream, powdered milk, nut pastes) can enrich normal foods without large volume increases. ^[2]
• Hydration and electrolytes support energy and reduce treatment‑related fatigue; address low sodium when present under clinical guidance. [PM14]
• Activity as tolerated may gently stimulate appetite and support digestion. ^[3]

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Key takeaways

• Weight loss can occur due to myeloma and its treatments, especially when nausea, vomiting, diarrhea, or poor appetite are present. ^[1] [PM14]
• Proactive nutrition strategies high-calorie/protein foods, small frequent meals, symptom control, and dietitian support are central to managing weight. ^{[2] [4] [3]}
• Promptly address uncontrolled symptoms such as nausea or diarrhea with your care team to prevent ongoing weight loss and maintain treatment tolerance. [PM14] [PM17]