How to Live on MREs for 21 Days? Lots of Water, Expert Says

Oregon Army National Guardsmen prepare hot meals and meals ready to eat (MREs) for soldiers during field training on Aug. 19, 2015, at the National Training Center in Fort Irwin, Calif. (U.S. Army photo/Anita VanderMolen)Oregon Army National Guardsmen prepare hot meals and meals ready to eat (MREs) for soldiers during field training on Aug. 19, 2015, at the National Training Center in Fort Irwin, Calif. (U.S. Army photo/Anita VanderMolen)

The Army is recruiting volunteers for a stomach-churning challenge: Eat nothing but meals-ready-to-eat for 21 straight days. For those brave enough to volunteer, military fitness expert Stew Smith has two tips: Stay active and stay hydrated.

The service announced its experiment in a Dec. 11 release. To study gut health and how bacteria in the stomach are affected by the military meals, the U.S. Army Research Institute of Environmental Medicine’s military nutrition division is recruiting volunteers to go on the all-MRE diet for three consecutive weeks.

According to criteria published by institute, volunteers must be between 18 and 62 years old and must not have prior gastrointestinal problems. They will receive up to $200 each to participate in the study. Apart from the shelf-stable meals, volunteers can consume only water and black coffee, according to a Military Times report.

MREs, designed to keep troops nourished during field training and in austere deployed environments, contain a gut-busting average of 1,250 calories apiece. Some claim the acronym stands for “meals refusing to exit” because of the binding effect repeated MRE consumption can have on the digestive system.

But Smith, a former Navy SEAL and military fitness trainer, said it’s possible to avoid the worst of the MRE side-effects by consuming lots of water and working off excess calories.

“You definitely want to drink water,” Smith told “Depending on how much you weigh, anywhere from a half-gallon to a gallon a day.”

As a good rule of thumb, he said volunteers should plan to drink half their weight in ounces — 100 ounces of water for a 200-pound man — and spread their water consumption out across the day.

The water, he said, will keep those on the MRE diet feeling good, and help to keep digestion regular, too.

For those consuming an MRE per meal, Smith said significant weight gain could be a problem if volunteers don’t counteract the calorie-dense packages with extra exercise. He noted that it’s also possible to lost weight on the MRE diet: Soldiers in Ranger school typically complete grueling training on just one MRE per day and can lose 35 pounds or more in the process.

For those who might struggle with boredom with the limited menu selection on the MRE-only diet, the Army has its own solution: The institute has developed a “cookbook” containing mix-and-match recipes using MRE staples. Volunteers can make their own “mountaineer mousse dip” using MRE pudding pouches or “Ranger red hot party mix” using nuts and MRE snacks.

Smith noted that MREs have the advantage of containing important elements of nutrition, including protein and electrolytes.

“I would rather eat an MRE for every meal of the day than get McDonald’s,” he said.

Find out more about the Army experiment here.

About the Author

Hope Hodge Seck
Hope Hodge Seck is a reporter at She can be reached at Follow her on Twitter at @HopeSeck.
  • Lance

    Hay MREs or C Rations for a month beats K Rations or Russian/Chinese rations for a month.

  • Leon Suchorski

    As long as they give me my tabasco sauce, I will eat any military meal.

  • Bo

    I lived off of MRE’s for nearly a month at the beginning for the war in Iraq.

  • DWJ

    Ate them for 120 days in Panama. Your stomach will be unhappy in week two and start to get used to them. At about 90 days I just quit eating the main meal and started living off the extras. By the end I was eating little and lost a ton of weight. The largest problem is starting a regular diet when you go off of them. i have not had an MRE since.

  • jas9360

    They don’t need to ‘study gut bacteria’…that’s proof, the bureaucracy is full of numb-skulls. They need only watch youtube video of the MREs being ‘evaluated’ by anyone…particularly the American ones…The answer is simple: there is absolutely no fiber content in those meals, and it is obvious to see that. Spending money on a study like this? – just shows there’s a lack of intelligence all round. Put some damned fiber into your MREs, problem solved. And, make sure, it is consistent – part of the military specification. What a bunch of dummies.

  • wtpworrier

    MRE side effects?…I ate MRE’s for a little while, before that C-rat’s and some K-rats…that’s what we called them, we never had any side effect from eating C’s, the taste could have been better but, other than that, we survived on them for a couple of months, sometimes longer. I always thought the trick to eating MRE’s was Tabasco sauce…lots and lots of Tabasco sauce, which was like gold back then. We had an old First Shirt that use to say…”Taking his Tabasco is an Act of War”.

  • JohnD

    Why waste the money on a test? Military troops have been doing this for years! You know the calorie count, you send out the surveys, so why do you waste money on this stupid test? Ancel Keys did it in WW2 because there was no data. Now there is tons of research! Total waste of limited funds and for what purpose? Do the math!

  • Yellow Devil

    What’s next? A study to see if any Servicemember can actually eat the egg omelet MRE for more then two straight days or ingest one serving of MRE crackers without any water?

  • ken

    Hell, I make more than $200 in one day. Screw that.

  • iac

    Nothing is really new.
    During WW2, Soldiers ate nothing but K Rations (ww2 version of First Strike Meals) for months; even though they were meant for just a few weeks, ,,,,,,, much like what happens with FS Meals !

  • Kyle

    Did this for a year back in ’90-’91 and got paid a whole lot more. Oh, that was while serving in USN in Desert Shield/ Storm. We used to call them “Meals rejected by Ethiopians”.

  • Marine64

    Ahhh, I miss my ration of C rats. MREs, never liked them in comparison.

  • Josh

    Wouldn’t bother me, the Iraq invasion in 03 we lived off them for months. Lots of times we’d just eat out of the bits box throughout the day instead of opening a new one every meal. Also agree on the copious amounts of water to consume; my most was about 3 gallons a day in that environment. What was air conditioning back then? Sure wasn’t where I was. I’ll also never have eaten a better tasting carrot, cucumber, or lettuce salad on an R&R than after months in the desert.

    • Larry

      A blast from the past about your lettuce salad comment…

      When my father returned to the States after WWII as a now battle tested LT they sent him home on a passenger liner. Sitting in the dining hall a steward came over and asked him what he wanted for lunch. Dad asked for half a head of lettuce and some mayonnaise. The steward asked if there was anything else he wanted and he said, “No, just the lettuce and mayo please. We haven’t seen each other in months and I wanted to get re-aquainted.” ; )


  • Josh

    The Aussies had really good MREs, the one I had contained a little thing of chicken ramen noodles and actual Juicy Fruit gum

  • Joe

    I ate nothing but MREs for more than six months and I am still here. My old Platoon SGT couldn’t because he had hemorrhoids.