A post-meal sugar level around 300 suggests that your diabetes is not well controlled right now, even while taking Metformin SR 500 regularly. Metformin SR is usually advised after food because taking it on an empty stomach may increase the chances of stomach pain, acidity, nausea, bloating, or loose motions. Taking it after meals also helps many people tolerate the medicine better during long-term use. Very high post-meal sugar may happen because of excess carbohydrates, irregular eating habits, stress, poor sleep, lack of exercise, infections, or progression of diabetes over time. Sometimes the current dose or treatment combination may no longer be enough for your body?s needs. Avoid increasing the dose on your own because improper adjustments may lead to side effects or sudden sugar fluctuations. Reducing sweets, sugary drinks, bakery foods, and large meal portions may help improve control. Regular walking after meals, proper sleep, hydration, and fixed meal timings can also naturally support better sugar stability.