Meal powder is the fine dust left over when black powder is corned and screened to separate it into different grain sizes. It is used extensively in various pyrotechnic procedures, usually to prime other compositions.
'Mill meal' powder is a mixture of KNO3, charcoal and sulfur in the correct proportions (75:15:10) which has been ball-milled to mix it intimately. It is used in the same way as commercial meal powder or can be pressed and corned to produce true black powder.
Meal replacements are pre-packaged powdered drink mixes that you mix with water, milk, or juice and then drink in the place of a meal.
Meal replacements provide a perfect, compact meal in a packet that is high in protein, low in fat (some have no fat) are low in carbohydrates, and contain a wide array of vitamins and minerals.
Stick with meals replacements that use a combination of whey, milk, and egg proteins as the first ingredient.