This is due to selective deposition of fat in your arm. There are many causes of such deposition such as increased food consumption without increasing physical activity, high junk food, Cushing’s syndrome, and hypothyroidism. There are many more uncommon causes. Advice 1. Increase physical activity – start physical activity in gym at least for half an hour for 4 – 5 days in a week regularly. Start with a balanced mix of cardio, weight training and flexibility exercises. Do more focus on your biceps and triceps 2. Avoid eating high energy foods such as cakes, chocolates, chips etc. 3. Avoid alcohol and smoking 4. Increase consumption of high fiber diet such as wheat bread, dry date, whole grain, and vegetables etc 5. Drink 3 – 4 liters of water daily 6. Divide your meals into smaller portions and eat them frequently during the day 7. Avoid oily & spicy food 8. Investigation – lipid profile, serum TSH & T4 Thanks