Meal Replacements are intended to replace a single meal, generally breakfast or lunch where the rest of the day's diet is made up of normal foods. They are usually in the form of biscuits, bars, drinks or mixes and contain between 200-400 kcal per 'meal' plus additional nutrients. They are not designed as complete dietary replacements but are enriched with major vitamins and minerals but not necessarily 100% of the recommended daily intake.

Meal replacements may sometimes be used twice in a day but should not be used as the sole source of nutrition. Most manufacturers provide suggested recipes for the other meals to ensure an adequate daily level of nutrients are consumed.

The key difference between Meal Replacements and products within the Low Calorie Programmes is that a Meal Replacement contains a defined complement of nutrients whereas products within a Low Calorie Programme have varying levels of nutrients to allow variety and choice in achieving a full day's nutritional requirements.