What is the maximum number of consecutive days that an MRE can be used as the sole source of nutrition?

The correct answer is based on guidelines regarding the use of Meals Ready-to-Eat (MREs) as a sole source of nutrition during situations where fresh food is not available. MREs are designed to provide complete nutrition for short-term use, but they are typically recommended for a maximum of 21 consecutive days when used exclusively.

This is due to the fact that while MREs contain essential nutrients, relying on them as the only food source for longer than 21 days can lead to potential deficiencies in certain vitamins and minerals, as well as digestive discomfort due to their high sodium content. It's important to ensure a diverse intake of food to meet all nutritional needs over extended periods. Hence, 21 days stands out as a practical and scientifically supported duration for using MREs alone without significant risk of nutritional deficits.