MREs and Dehydration: The Misconception vs. The Reality
While the popular belief that MREs, or Meals, Ready-to-Eat, cause dehydration is widespread, the reality is more nuanced. MREs themselves do not actively pull water from your body. The issue arises from their specific nutritional profile, which is engineered for a particular purpose: fueling highly active military personnel in extreme conditions. The combination of a high sodium content and a distinct lack of fiber, when not balanced with sufficient fluid intake, can lead to the symptoms of dehydration and digestive problems.
Unlike freeze-dried foods that require rehydration, MREs are fully cooked and contain moisture. However, this moisture is not enough to offset the effects of a diet consisting solely of these high-sodium, low-fiber meals. For the average civilian or someone in a less active emergency scenario, this can be a serious concern.
The High Sodium Factor and Fluid Requirements
One of the most significant reasons a person might feel dehydrated when eating MREs is the extremely high sodium content. The sodium is used both for flavor enhancement and as a preservative to give the meals their long shelf life.
How high sodium impacts hydration:
- Increased Water Demand: Excess sodium in the bloodstream triggers thirst and increases the body's need for water to maintain a proper electrolyte balance. If you don't drink enough water to compensate, your body will begin to show signs of dehydration.
- Different Needs: The high sodium is less of a concern for soldiers engaged in intense physical activity, as they are constantly sweating and losing electrolytes, which the MREs help replenish. For inactive civilians, however, this excess sodium can pose a health risk, especially for those with high blood pressure.
The Fiber Factor and Constipation
Another component of the MRE diet that contributes to digestive discomfort and, indirectly, to hydration issues is the low fiber content. The military colloquially refers to MREs as "Meals, Refusing to Exit" due to their constipating effects.
The link between low fiber, constipation, and fluid balance:
- Hard Stools: Fiber adds bulk to stool and helps it pass smoothly through the digestive tract. Without sufficient fiber, stools can become hard and difficult to pass, leading to constipation.
- Digestive Strain: The digestive system requires adequate fluids to function properly. When fiber is low and fluid intake is poor, the body pulls water from the colon to aid digestion, exacerbating both constipation and systemic dehydration.
Comparison: MREs vs. Dehydrated and Freeze-Dried Meals
It's important to understand the fundamental differences between these types of emergency foods, particularly regarding their hydration impact.
| Feature | MREs (Meals, Ready-to-Eat) | Dehydrated/Freeze-Dried Meals |
|---|---|---|
| Water Requirement | No added water needed for preparation; critical for mitigation of high sodium/low fiber. | Requires water (often boiling) for preparation and rehydration. |
| Moisture Content | High moisture retained from cooking process. | Moisture is almost completely removed to reduce weight and extend shelf life. |
| Weight & Bulk | Heavier and bulkier due to retained water and retort packaging. | Extremely lightweight and compact, making them ideal for backpacking. |
| Shelf Life | ~5-7 years, with some varieties lasting longer if stored properly. | Up to 25+ years due to near-total moisture removal. |
| Taste & Texture | Considered superior to rehydrated meals, more like canned food. | Can sometimes have a rubbery or reconstituted texture. |
Strategies to Prevent Dehydration with MREs
To avoid feeling the ill effects of an MRE-based diet, especially over a prolonged period (which is not recommended beyond 21 days), you must be proactive with your hydration. The following steps can help:
- Conscious Water Intake: Don't wait until you are thirsty. Thirst is a lagging indicator of dehydration. Make a conscious effort to consume water throughout the day, especially with and between your meals.
- Utilize Drink Mixes: Most MREs come with powdered drink mixes. These are often fortified with electrolytes, which help your body better absorb and retain fluid. Use them as intended.
- Monitor Urine Color: Your urine is an excellent indicator of your hydration level. A pale yellow color, similar to lemonade, indicates you are well-hydrated. Darker yellow urine suggests you need to increase your fluid intake.
- Supplement with Water-Rich Foods: If possible, supplement your MRE diet with fresh foods that have a high water content, such as fruits and vegetables. This also introduces much-needed fiber.
- Avoid Caffeinated Drinks: Coffee and tea found in MREs contain caffeine, which is a diuretic. While a small amount is unlikely to be harmful, excessive consumption can increase fluid loss.
For more in-depth information on military nutrition and performance, the Defense Technical Information Center offers valuable research.
Conclusion: The Final Word on MREs and Dehydration
While MREs are an invaluable tool for military personnel, survivalists, and emergency responders, they are not a perfect food source. They do not directly dehydrate you, but their high sodium and low fiber content create a nutritional landscape where adequate hydration is absolutely critical. Failing to drink enough water will lead to digestive issues and the symptoms of dehydration. By understanding the composition of MREs and consciously prioritizing your fluid intake, you can effectively manage their drawbacks and use them safely as an emergency food source.
