Weight Loss with Myasthenia Gravis in South Africa

Myasthenia gravis (MG) is an autoimmune neuromuscular disease in which the body's immune system attacks the communication points between nerves and muscles — the acetylcholine receptors. The result is characteristic muscle weakness that fluctuates throughout the day, typically worst in the evening and better in the morning. For South Africans living with MG, managing weight is a real challenge: the medications that control the disease can drive weight gain, muscle weakness limits activity, and swallowing difficulties can complicate eating entirely.

This guide navigates the specific weight challenges of myasthenia gravis with practical strategies adapted to the South African context.

The MG Weight Puzzle: Why the Scales Move in the Wrong Direction

Weight gain in myasthenia gravis has several overlapping drivers:

• Corticosteroids (prednisone/prednisolone) — the backbone of MG immune suppression. Long-term steroid use increases appetite significantly, causes fluid retention, redistributes fat to the abdomen, back of the neck ("buffalo hump"), and face ("moon face"), and accelerates muscle loss. Patients on 20 mg+ per day commonly gain 5–15 kg over the first year of treatment.
• Reduced physical activity — MG causes fluctuating weakness in limb, bulbar, and respiratory muscles. On bad days, even walking to the kitchen is exhausting. This inactivity reduces caloric expenditure and accelerates muscle wasting.
• Dysphagia (swallowing difficulty) — up to 40% of MG patients experience bulbar muscle involvement affecting chewing and swallowing. This can paradoxically lead to either weight loss (not eating enough) or weight gain (gravitating toward easy-to-eat, calorie-dense soft foods like ice cream, mashed potato with butter, and soft white bread).
• Post-thymectomy changes — some patients gain weight after thymectomy as disease control improves and appetite normalises.

Eating Well with Myasthenia Gravis

Managing Corticosteroid-Driven Weight Gain Through Diet

When steroids are non-negotiable, dietary strategy becomes the primary lever for weight control. Evidence-backed approaches include:

• Reduce sodium to under 2,000 mg/day — steroids cause sodium and fluid retention. Cutting salt dramatically reduces water weight. South African diets tend to be high in sodium (processed meats, tinned fish, packet soups, crisps). Read labels and cook from fresh ingredients where possible.
• High protein, moderate carbohydrates — steroids increase muscle protein breakdown. Counteract this with 1.5–2 g of protein per kg of body weight daily, using lean sources: chicken breast, hake, eggs, low-fat cottage cheese (Lancewood or similar SA brands), and low-fat yoghurt (Woolworths, Pick n Pay private label).
• Choose complex carbohydrates — brown rice, oats, and legumes have a lower glycaemic load than the white bread and refined starches that dominate many South African diets. This helps manage the blood sugar spikes that steroids exacerbate.
• Limit saturated fat and added sugar — steroids worsen cholesterol profiles. Focus on olive oil, avocado, and omega-3 rich fish (pilchards in tomato sauce — affordable and widely available in SA — are an excellent choice).
• Calcium and vitamin D — steroids leach calcium from bone. Ensure adequate calcium intake (3–4 servings of dairy per day or fortified plant alternatives) and discuss vitamin D supplementation with your specialist. Bone health monitoring (DEXA scan) is standard in long-term steroid users.

Dysphagia-Safe Eating

When bulbar muscles are affected, eating becomes slow, tiring, and carries aspiration risk. Practical strategies:

• Time meals to medication peaks — pyridostigmine (Mestinon) typically peaks 1–2 hours after ingestion. Plan your main meal during this window when muscle strength is best.
• Soft, high-protein options for South Africans: scrambled eggs, soft-boiled eggs, smooth peanut butter on soft bread, thick yoghurt (Fage or similar), flaked hake with sauce, soft mealie pap (maize porridge) with full-cream milk, smooth hummus, and smooth nut butters.
• Avoid: dry biscuits (Tennis biscuits, Marie biscuits without milk), tough steak, crispy roast chicken skin, mixed textures (soup with chunky vegetables), and dry bread rolls.
• Sit upright during and for 30 minutes after eating — reduces aspiration risk.
• Small, frequent meals — 5–6 small meals rather than 3 large ones reduces jaw and swallowing fatigue per eating episode.
• Speech-language therapist referral — if dysphagia is significant, request a swallowing assessment (videofluoroscopy or FEES) at your academic hospital. This can guide specific texture recommendations.

Exercise with Myasthenia Gravis: Work With Your Windows

The fluctuating nature of MG muscle weakness means that exercise must be strategically timed and carefully dosed. The good news: the right kind of exercise is not only safe but actively beneficial for strength maintenance, mood, and metabolic health.

Timing is Everything

• Exercise in the morning when MG-related fatigue is typically lowest.
• Schedule activity 1–2 hours after taking pyridostigmine when the medication is at its peak effect.
• Never exercise to the point of muscle exhaustion — MG weakness is cumulative within a session and can trigger exacerbation.

Best Exercise Types for MG

• Swimming and water aerobics — the gold standard for MG. Water supports body weight, keeps you cool (heat worsens symptoms), provides resistance for strength without impact, and is easy to scale down when having a bad day. Many SA municipal pools and Virgin Active/Planet Fitness gyms have heated pools.
• Walking — start with 10–15 minute flat walks. Progress to 30 minutes over weeks. Use a shopping centre for air-conditioned walking if Gauteng/Western Cape summer heat is a trigger.
• Light resistance training — with neurologist and physiotherapist guidance, seated resistance work with light weights or resistance bands maintains muscle mass that steroids deplete. Focus on upper body and core.
• Yoga and stretching — gentle yoga improves flexibility and reduces the joint pain that comes with inactivity, without the exertion risk of aerobic exercise.

What to Avoid

• Extreme heat — outdoor exercise in SA summer (December–February in Gauteng and Free State where temperatures exceed 35°C) can trigger myasthenic crises. Swim, use air-conditioned gyms, or exercise before 08:00 or after 18:00.
• High-intensity interval training (HIIT) — the explosive intensity pattern is poorly suited to MG. Steady-state moderate activity is safer and more sustainable.
• Exercising alone when symptomatic — always have someone nearby during exercise if you are in a period of active MG symptoms.

Understanding Your MG Medications and Weight

Pyridostigmine (Mestinon)

Pyridostigmine is a cholinesterase inhibitor that improves neuromuscular transmission. It is typically the first medication started and does not cause weight gain directly. However, its cholinergic side effects — increased saliva, loose stools, nausea, and stomach cramping — can reduce appetite in some patients. In South Africa, Mestinon 60 mg tablets are available through specialist pharmacies at approximately R800–R1,400/month depending on dose and scheme cover.

Prednisone / Prednisolone

As discussed above, the primary driver of weight gain in MG. Your neurologist will aim to reduce to the lowest effective dose over time (alternate-day dosing reduces side effects). Do not stop or reduce steroids without specialist guidance — this can precipitate a myasthenic crisis.

Immunosuppressants (Azathioprine, Mycophenolate)

These steroid-sparing agents are used to reduce prednisone doses over time. Azathioprine (Imuran) can cause nausea, particularly early in treatment. Mycophenolate mofetil (CellCept) similarly may cause GI upset. Neither drug directly causes weight gain, and their steroid-sparing effect may ultimately help with weight management as steroid doses come down.

Rituximab and Eculizumab

Newer biologic agents for refractory MG. Both are available in South Africa through specialist infusion centres and are covered under certain medical aid PMB and oncology/rare disease benefit structures. Weight effects are generally minimal.

Red Flags: Medications to Avoid in MG

Some commonly prescribed and over-the-counter medications can worsen myasthenia gravis. If you are considering any supplement, antibiotic, or medication for weight management, discuss with your neurologist first. Known exacerbators include:

• Fluoroquinolone antibiotics (ciprofloxacin, levofloxacin) — widely prescribed in SA for UTIs
• Aminoglycosides (gentamicin, tobramycin)
• Beta-blockers (propranolol, atenolol)
• Magnesium supplements (in large doses)
• Chloroquine / hydroxychloroquine
• Stimulant weight-loss supplements containing ephedrine, synephrine, or high-dose caffeine

Finding Support in South Africa

• Myasthenia Gravis Foundation of South Africa (MGFSA): Patient support, information resources, and specialist referral guidance.
• Neurology departments: Charlotte Maxeke Johannesburg Academic Hospital, Groote Schuur Hospital, Inkosi Albert Luthuli Central Hospital (Durban), Steve Biko Academic Hospital (Pretoria).
• ADSA Registered Dietitian: Essential for a personalised eating plan that addresses both the low-salt, high-protein steroid diet and any swallowing restrictions. Find one at adsa.org.za.
• Physiotherapist: A physio experienced in neurological conditions can design a safe, progressive exercise programme. Ask your neurologist for a referral.
• PMB Status: Myasthenia gravis qualifies as a Prescribed Minimum Benefit (PMB) condition. Your medical aid must cover diagnosis, specialist management, and treatment at cost. Confirm with your scheme's disease management team.

Key Takeaways

• Corticosteroids are the main driver of weight gain in MG — counter this with a high-protein, low-sodium, complex-carbohydrate diet.
• Time meals to pyridostigmine peaks; use soft, easy-to-chew foods if bulbar muscles are affected.
• Exercise is safe and beneficial: swim, walk, or use light resistance training in the morning and in cool environments.
• Avoid heat, HIIT, and high-dose stimulant supplements — all can worsen MG symptoms.
• Several common antibiotics (fluoroquinolones) and supplements exacerbate MG — always check with your neurologist before adding anything new.
• MG is a PMB condition — your medical aid must cover treatment costs.

Frequently Asked Questions

Why do people with myasthenia gravis gain weight?

The primary driver is long-term corticosteroid use (prednisone). Steroids increase appetite, cause fluid retention, redistribute fat to the abdomen and face, and promote muscle loss. Reduced physical activity due to muscle weakness compounds the problem.

Is it safe to exercise with myasthenia gravis?

Yes, with appropriate precautions. Exercise in the morning when energy is highest, keep sessions short (15–20 minutes), avoid exercising to the point of muscle fatigue, and stay cool — heat worsens MG symptoms significantly. Swimming and water aerobics are particularly well-suited. Always get clearance from your neurologist before starting a new programme.

What should I eat if I have swallowing difficulties from MG?

A texture-modified diet is recommended during periods of dysphagia. Choose soft proteins (scrambled eggs, soft fish, smooth peanut butter, yoghurt), mashed or pureed vegetables, and well-cooked oats or soft mealie pap. Avoid dry, crumbly foods that increase aspiration risk. Sit upright and eat when medications are at their peak effect.

Does pyridostigmine (Mestinon) affect weight?

Pyridostigmine itself does not cause weight gain. However, its cholinergic side effects — increased saliva, nausea, stomach cramping, and diarrhoea — can reduce appetite and affect calorie absorption in some patients, particularly at higher doses.

Where can people with myasthenia gravis get support in South Africa?

The Myasthenia Gravis Foundation of South Africa (MGFSA) provides patient support and specialist referral guidance. Neurologists at academic hospitals manage MG. The condition qualifies as a Prescribed Minimum Benefit (PMB) under South African medical aid regulations.