Can you lose weight with myositis?

Yes, but the approach must be carefully calibrated. With polymyositis or dermatomyositis, rapid weight loss risks accelerating muscle wasting — already a central feature of the disease. The goal is slow, steady fat loss (no more than 0.3–0.5 kg per week) while actively protecting and rebuilding muscle through adequate protein intake and graded physiotherapy-supervised exercise during remission phases.

What should I eat with polymyositis or dermatomyositis?

An anti-inflammatory diet is the foundation: oily fish (pilchards, sardines, salmon), colourful vegetables, legumes, olive oil, nuts, and berries. Protein must be prioritised — 1.2–1.6 g per kg body weight daily — to counteract muscle breakdown. SA-friendly sources include eggs, lentils, samp and beans, low-fat dairy (amasi, maas), and canned tuna or pilchards. Limit ultra-processed foods, refined carbohydrates, and added sugar, which all promote systemic inflammation.

Can I exercise with myositis?

Exercise must be matched to disease activity. During active flares with elevated CK (creatine kinase), strenuous exercise can worsen muscle damage — rest and physiotherapy-guided gentle range-of-motion work is appropriate. During remission, supervised resistance training (even light bands or water resistance) and swimming are well evidenced to improve muscle strength and function without triggering relapse. Always clear any new exercise programme with your rheumatologist and physiotherapist.

Does myositis cause weight gain?

Myositis itself tends to cause muscle loss rather than fat gain, but the medications used to treat it — particularly high-dose prednisone — frequently cause significant weight gain. Corticosteroids increase appetite, redistribute fat to the abdomen and face, cause fluid retention, and promote insulin resistance. Managing steroid-related weight gain requires a low-sodium, moderate-carbohydrate, high-protein diet combined with whatever physical activity your disease activity permits.

What does myositis treatment cost in South Africa?

First-line therapy is prednisone (affordable, under R100/month at most pharmacies) plus methotrexate or azathioprine (R150–R500/month). Refractory cases may need IVIG (intravenous immunoglobulin), which costs R8,000–R25,000 per infusion in SA — typically 2-day courses every 4–8 weeks. Rituximab is sometimes used off-label (R15,000–R40,000 per infusion). Medical aid schemes must cover myositis as a prescribed minimum benefit (PMB) condition — check with your scheme's case manager.

Weight Loss with Myositis in South Africa

Myositis — an umbrella term covering polymyositis (PM) and dermatomyositis (DM) — is an inflammatory muscle disease that makes everyday movement painful, exhausting, and sometimes dangerous. When your immune system attacks your own muscle fibres, losing weight while preserving what little muscle strength you have becomes a delicate balancing act. Add in the weight gain that often accompanies high-dose corticosteroid treatment, and you have a genuinely complex nutritional puzzle to solve.

This guide is written for South Africans living with PM or DM who want practical, evidence-based advice on eating, exercise, and managing medication-related weight changes — without risking a relapse.

Always work with your rheumatologist, a registered dietitian (RD), and a physiotherapist before making significant changes to your diet or exercise routine.

What Myositis Does to Your Body Weight

Polymyositis and dermatomyositis cause immune-mediated destruction of skeletal muscle fibres. The practical consequences for body composition are significant:

Muscle wasting: Active inflammation breaks down muscle protein faster than the body can rebuild it, reducing lean mass and lowering your resting metabolic rate.
Reduced physical capacity: Proximal muscle weakness (hips, thighs, shoulders, upper arms) makes climbing stairs, rising from a chair, and lifting objects difficult — reducing daily calorie burn.
Dysphagia: Up to 30% of people with PM/DM develop oropharyngeal dysphagia (swallowing difficulty) due to pharyngeal muscle involvement. This limits the texture and volume of food safely consumed, creating a nutritional challenge.
Corticosteroid weight gain: High-dose prednisone — the backbone of initial treatment — causes appetite stimulation, abdominal fat deposition, fluid retention, and insulin resistance, often adding 5–10 kg in the first months of therapy.

Nutrition Strategy: Protecting Muscle While Reducing Fat

The single most important dietary principle with myositis is do not calorie-restrict aggressively. A large calorie deficit accelerates muscle breakdown — exactly the opposite of what you need. Instead, aim for a modest deficit of 300–500 kcal/day to achieve 0.3–0.5 kg of fat loss per week, while hitting high protein targets.

Protein: Your Priority Nutrient

Research in inflammatory myopathies supports protein intakes of 1.2–1.6 g per kg of body weight per day — significantly higher than the general population recommendation of 0.8 g/kg. For a 75 kg person, that is 90–120 g of protein daily.

Cost-effective, SA-accessible protein sources:

Eggs — complete protein, R30–R50 per dozen; scrambled or poached for dysphagia-friendly texture
Canned pilchards and sardines — R15–R25 per 400 g tin; also provide anti-inflammatory omega-3 fatty acids
Samp and beans — traditional SA combination providing complementary amino acids; affordable and accessible nationwide
Lentils and split peas — R20–R35 per 500 g; easy to cook soft for dysphagia
Maas and amasi (fermented milk) — 10–15 g protein per 250 ml; probiotic benefit supports gut health during immunosuppression
Chicken breast (skinless) — R60–R100 per kg; easy to shred or mince for soft textures

Anti-Inflammatory Eating Pattern

Beyond protein, an anti-inflammatory dietary pattern helps modulate the immune overactivity underlying myositis. The Mediterranean diet has the strongest evidence base and adapts well to South African eating habits:

Oily fish 3x/week: Pilchards, sardines, snoek, salmon — omega-3 fatty acids (EPA and DHA) reduce inflammatory cytokine production
Colourful vegetables daily: Spinach, tomatoes, butternut, beetroot, sweet potato — rich in antioxidants and phytonutrients
Legumes: Lentils, chickpeas, black-eyed beans — fibre and plant protein
Extra virgin olive oil: Primary cooking fat; oleocanthal has NSAID-like anti-inflammatory properties
Turmeric and ginger: Add to curries, soups, rooibos tea — curcumin and gingerol have modest anti-inflammatory activity
Rooibos tea: Caffeine-free, rich in aspalathin and quercetin; a genuinely SA anti-inflammatory beverage

Limit or avoid: Ultra-processed foods, refined sugars, commercial frying oils (sunflower, palm), and alcohol — all promote systemic inflammation.

Eating with Dysphagia

If myositis has affected your swallowing muscles, texture modification becomes essential. A speech-language therapist (SLT) assessment is recommended — they will prescribe an IDDSI (International Dysphagia Diet Standardisation Initiative) level appropriate for your degree of dysphagia.

Soft, high-protein options for dysphagia-friendly eating in SA:

Smooth pap with maas or egg — add cream cheese for calories
Soft scrambled eggs with pureed spinach
Lentil or split pea soup (blended smooth)
Avocado mashed with canned tuna
Custard or smooth yoghurt fortified with protein powder
Soft ripe banana mashed with peanut butter

Managing Corticosteroid-Induced Weight Gain

Prednisone is life-saving in myositis but notorious for weight gain. Practical strategies to minimise the damage:

Low sodium diet (<2,000 mg/day): Steroids cause sodium retention and fluid retention — cutting salt reduces puffiness and bloating significantly. Avoid table salt, salty stocks, processed meats, and takeaways.
Moderate carbohydrates, choose low-GI: Steroids worsen insulin sensitivity. Swap white bread, white rice, and sugary drinks for oats, sweet potato, brown rice, and basmati rice.
Eat at set times: Prednisone creates persistent hunger signals. Structured meals with protein and fibre at every sitting reduce the drive to snack between meals.
Take prednisone with food in the morning: Reduces appetite stimulation throughout the day compared to evening dosing.
Monitor blood glucose: Steroid-induced diabetes (steroid diabetes) can emerge — particularly in those already at risk. Ask your doctor about monitoring, especially if you are gaining weight rapidly.
Calcium and vitamin D supplementation: Long-term corticosteroids deplete bone density; most myositis patients are prescribed calcium 1,000 mg + vitamin D 800–1,000 IU daily. Confirm with your prescriber.

Exercise: Matching Activity to Disease Activity

Exercise recommendations in myositis have evolved significantly. The old advice of complete rest during treatment is now known to be harmful — prolonged inactivity accelerates muscle wasting. However, exercise must be matched to your current disease state:

During Active Flares (Elevated CK, Active Inflammation)

Gentle range-of-motion exercises guided by a physiotherapist
Hydrotherapy (warm water pool) — reduces gravitational load on inflamed muscles
No high-intensity or resistance training — can worsen muscle damage when CK is elevated

During Remission (Stable CK, Well-Controlled Disease)

Progressive resistance training — start with theraband exercises, progress to light weights
Swimming and water aerobics — excellent low-impact option; pool humidity also benefits dermatomyositis skin
Walking: start at 10–15 minutes, progress gradually
Chair-based exercises for those with significant proximal weakness

Always have CK levels checked before intensifying exercise. SA government hospitals (most have physiotherapy departments) and private physiotherapy practices both offer supervised rehabilitation programmes.

Dermatomyositis-Specific Considerations

Dermatomyositis involves characteristic skin changes — heliotrope rash (purple-red eyelids), Gottron's papules (knuckle rash), and photosensitivity — in addition to muscle inflammation. For weight management this means:

Sun avoidance for exercise: Exercise outdoors only in early morning or late evening; avoid the 10 am–4 pm SA summer sun that can trigger skin flares
Pool exercise: Swimming provides both exercise and humidified environment beneficial for skin, but apply broad-spectrum SPF 50+ sunscreen to exposed areas poolside
DM and malignancy screening: Adult-onset DM has a meaningful association with underlying malignancy — your doctor should screen appropriately. This context makes any rapid unexplained weight loss especially important to report

Treatment Costs and Medical Aid Coverage in South Africa

Myositis treatment spans a wide cost range depending on severity:

Prednisone: R30–R100/month — generic, widely available at government pharmacies
Methotrexate: R150–R350/month on chronic prescription
Azathioprine (Imuran): R200–R500/month
Hydroxychloroquine (used in some DM cases for skin): R200–R450/month, CDL-listed for qualifying diagnoses
IVIG (intravenous immunoglobulin): R8,000–R25,000 per treatment course — requires prior authorisation from your medical aid
Rituximab: R15,000–R40,000 per infusion; used off-label in refractory myositis — medical aid motivation required

Myositis qualifies as a Prescribed Minimum Benefit (PMB) condition under the Medical Schemes Act. This means your medical aid must fund diagnosis and treatment at cost, regardless of benefit limits. Contact your scheme's case management team to ensure you are getting all entitled benefits.

SA Resources and Support

SARAA (South African Rheumatism and Arthritis Association): saraa.org.za — rheumatologist directory and patient information
ADSA (Association for Dietetics in South Africa): adsa.org.za — find a registered dietitian experienced in chronic inflammatory disease
SASP (South African Society of Physiotherapy): saphysio.co.za — find a physiotherapist experienced in neuromuscular conditions
SADAG (South African Depression and Anxiety Group): sadag.org — for mental health support; chronic pain and disability carry high rates of depression and anxiety