What if carbs upset my stomach during training?
GI distress usually means the dose, concentration, timing, or food type is wrong for you. Start smaller. Move solid food farther from training, choose lower-fat and lower-fiber pre-workout meals, and use liquids or gels only when they are actually needed.
For drinks, concentration matters. Very concentrated carbohydrate drinks can sit heavily in the stomach. Diluting the drink, sipping gradually, using a different carbohydrate source, or training the gut over several weeks can help. For most lifters, the answer is often simpler: eat a normal meal 2-4 hours before training and skip intra-workout carbs unless the session is long enough to justify them.