Emergency Food

On deployment or expedition, it is standard protocol to carry some emergency rations. This is typically in the form of an expired Mars Bar. But we can do better than that.

When managing or preventing a cold and/or hypoglycaemic casualty in a remote environment a few well-chosen items can make a big difference in terms of the speed of recovery, sustained benefit of that recovery and morale.

Simple vs Complex Carbohydrates

Conventional wisdom suggests that ingestion of simple sugars can provide a rapid peak in blood-glucose levels and that the use of complex carbohydrates provides a longer, more stable increase of blood-glucose levels. Both suppositions share an assumption that fluctuations in blood glucose levels parallel and mediate the emergence of peaks and troughs in physical and mental performance.

Simple sugars
Simple carbohydrates in sweet snack foods are touted to generate a burst of energy - the “sugar rush” that directly results from a steep rise in blood glucose levels. Extrapolation of this metaphor, that blood sugar energizes metabolic processes, sugar become regarded as an ‘energizer’ for both physical and mental performance, (1) although the evidence for this is minimal at best (2, 3).

Conversely, simple sugars have a reputation for being short-acting, resulting in a stark “sugar-crash” an overproduction of insulin as a consequence of the extreme glucose fluctuation (4, 5). This ‘reactive hypoglycemia’ is clinically rare in healthy humans (6) but can be common in those with diabetes or can be seen as an indicator of pre-diabetes.

A much more common and likely cause of the “crash” is postprandial somnolence - the Food Coma - a general state of low energy related to activation of the parasympathetic nervous system in response to mass in the gastrointestinal tract. While there are numerous theories surrounding this behavior, the most likely causes are decreased blood flow to the brain, neurohormonal modulation of sleep through digestive coupled signaling, or vagal stimulation (7).

Complex Carbohydrates
Whereas the supporting evidence for the sugar spike and crash of simple carbohydrates is sparse, there is some supporting evidence that more complex carbohydrates do sometimes produce a more moderated release of glucose, and as such, a less dramatic rise in insulin, yielding a more sustained source of energy.

Some foods traditionally thought of as complex carbohydrates, such as wholegrain bread (GI 52), have a lower glycemic index than simple carbohydrates, such as glucose (GI 100). The glycemic indices for other complex carbohydrates, such as potato (GI 80-90), are actually higher than sucrose (refined white sugar (GI 65)) and some conventionally complex carbs such as white bread and muesli (GI 65) have a similar GI.

They’re just carbs.

Simple sugars such as glucose and sucrose will be made available for cell use quicker than more complex sugars such as lactose and fructose. But don’t get hung up about a ‘sugar crash’ or, indeed, expect typically complex carbs to provide more sustained release. Other factors including fiber content, food form, digestibility, cooking method, and eating rate critically influence the glycaemic response and, as a consequence, the rate of energy release.

What is unquestioned is that carbohydrates - regardless of complexity - are digested quicker than fats and proteins, which is the real issue. Work by Qamar (8) examined gastric activity following ingestion of carbohydrates, fats and proteins after a period of fasting by measuring blood-flow in the mesenteric artery; the maximal responses were not significantly different but were reached at different times following ingestion: carbohydrate, 64% at 15 min; fat, 60% at 30 min; and protein, 57% at 45 min.

Carbohydrates will be digested quicker than fats and proteins but in order to extract energy, fats and proteins will need to go through several additional chemical reactions, which carbohydrates do not.

The Krebs Cycle is the process of creating Adenosine Triphosphate - the primary energy source for most cells.

During the process, one molecule of glucose is converted into two molecules of pyruvic acid, generating energy in the form of two net molecules of Adenosine Triphosphate (ATP). Four molecules of ATP per glucose are actually produced, but two are consumed as part of the process.

Fats for energy

Where carbohydrates are quickly broken into glucose which can easily enter the Krebs Cycle, fats are the slowest digesting of the three macronutrients, but they are also the most efficient. Every gram of dietary fat supplies the body with about 9 calories compared to 4 calories per gram of carbohydrate and protein. Your body will preferentially utilise the glucose from carbohydrates as it is the most freely available to replenish the muscle glycogen stores.

Fats, on the other hand, require complex reactions to access the stored energy.

In the intestine, fats are broken down into fatty acids and glycerol. These fatty acid chains are converted into energy via a process called beta-oxidation into Acetyl-CoA before they can enter the Krebs cycle along with oxygen to create ATP.

Proteins for energy

Protein can be metabolized and used as an energy source for the body, but it’s not the preferred source of energy.

Proteins are broken down into individual amino acids; about 75% of which are used to synthesize new proteins which are used to build and repair tissues. They're also used to produce enzymes that digest food and activate your metabolism.

Only a small amount of carbohydrates (about 1,200-2,000 calories worth) can be stored in the liver and muscles as glycogen (9); in the absence of enough carbs, our body’s next preferred energy source is fats.

Under ordinary circumstances, our bodies only use protein for a small amount of daily energy - around 5% of daily energy. During strenuous activity, if glycogen stores are depleted, protein can provide up to 15% of energy (9). As protein is not a quick or efficient source of fuel, and since it can’t be stored, any protein consumed that doesn’t get used immediately is converted into fat for storage.

Protein is still key to maintaining a healthy energy level as it impacts the way we metabolize other nutrients.

Tactical Snack Pack

OK. They're just snacks but everything is Tacticool now. And if they are vacuum packed, they're Deployment Tactical Snacks.

A casualty who requires energy also requires proteins and fats. If you think about a time you have ever been hungry or cold, you are probably not craving a tablespoon of sugar. You are probably craving lasagne or a curry. Your body is craving real food and so is a cold and/or hungry casualty.

Energy and macronutrient needs must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue. Fat intake should be sufficient to provide the essential fatty acids and fat-soluble vitamins and to contribute energy for weight maintenance. (10)

Overall, diets should provide moderate amounts of energy from fat (20% to 25% of energy); however, there appears to be no health or performance benefit to consuming a diet containing less than 15% of energy from fat (11).

While we can’t carry an emergency lasagne, we can certainly do better than an out-of-date chocolate bar and some boiled sweets.

Requirements

• Size and Weight
  The pack should be small and light so carrying it does not become an inhibitor. As an emergency food, it should not be as large as your daily rations or packed lunch.

• Packaging
  It should be packaged as small and tight as possible to reduce bulk. It should also be waterproof and durable to tolerate being left in the lid of a rucksack for weeks or months at a time. Vacuum packaging achieves all of this and also increases the shelf-life. Vacuum packing also creates a psychological barrier to prevent people from dipping into it when they are just a bit peckish.

• Contents

  Items should be dense to not only maximise the calorie to weight ratio without sacrificing bulk but also to reduce damage when they are squashed. They should have a long life and not be affected by extremes of heat. No one wants melted chocolate or a squashed sandwhich.

• Morale
  There is a school of thought that emergency rations should be unappealing, to prevent someone from eating them unnecessarily. While there is merit here, it is difficult to explain the profound benefit to the casualty and the group in being able to raise morale with some simple treats or luxuries.

Contents

Hypoglycemia and Hypothermia:
Both of these casualties need high-GI sugars like glucose which can be obtained from Haribos or energy gels. But these fast-acting sugars need to be backed up with low-GI carbs, fats and protein for sustained energy and to aid metabolism. These can be sourced conveniently from cereal bars, nuts and seeds, protein bars and biltong.

Further reading - Understanding Diabetes

Further reading - Hypothermia Guidelines

Dehydration
Most people, eating a normal diet, are not electrolyte depleted when they are dehydrated as we consume our electrolytes in our food. We should also take a much more judicious approach than just giving Dioryalyte to every casualty. However, a casualty with D&V, an endurance athlete surviving on protein bars and energy gels alone or a traveler in a hot environment who is not eating a normal diet "because it tastes funny" may all be electrolyte depleted.

Further reading - Heat Illness

Carrying sachets is not only smaller and lighter than bottles fluids you can also adjust the concentration. A casualty with Exercise Associated Hyponatraemia is electrolyte depleted but over-hydrated. You can give them a sachet in a shot of water without exacerbating the over-hydration.

Further reading - Exercise Associated Hyponatraemia

Caffeine
There is limited evidence that caffeine can enhance the effects of mild analgesia (12, 13) and improve respiratory effort (14) and heart contractility (15).

And sometimes, you just need a caffeine hit - especially on a night exercise or long shift. Caffeine gum is small, convenient, lightweight and does not require a brew-kit.

Peanut Butter

Carrying a significant amount of calories typically incurs a weight penalty. Several companies now produce peanut butter in a squeezy pouch, marketed towards athletes. But it is just peanut butter, albeit in a convenient package.

Similar to the carbohydrate rich Plumpy’Nut Ready-to-use Therapeutic Food (RUTF) used by aid agencies for severe cases of malnutrition in areas of famine and civil displacement, peanut butter is also relatively digestible, compared to protein bars and biltong albeit not as palatable. One would have to be pretty desperate to work your way through three or four of these a day to meet your calorific requirement.

Any generic supermarket peanut butter will do and can be decanted into a resealable pouch such as these but for convenince, Fuel10k Peanut Butter represents the best value at £1.50 for a 225g pouch compared to Resilient Nutrition’s offering at £4.99 for a 100g pouch. The Resilient Nutrition offer doesn’t actually contain peanuts, instead almonds, cashews, hazelnuts and pecans which are more expensive but less likely to trigger allergies.

There are fewer ways to carry such calorie-dense foods for such a low weight compromise with a reasonably long shelf life.

Homemade Emergency Food

“Sniper Slurry” is derived from the mix of basic foods snipers would keep in a bag in their pocket to munch on throughout the day or night where movement would give away their position….if you believe the legend. A rudimentary emergency, high-calorie food can be made from a mix of rolled oats, honey and peanut butter. Anecdotally coffee would be added to maintain mental acuity. All of these ingredients can be sourced in comparatively resource-poor areas.

This can be vacuum packed for longevity and can be eaten dry, straight from the bag similar to a dense trail mix, broken into milk as a cereal or cooked with hot water to make a calorie-dense porridge. Tinkering with the mix can yield a basic 50:30:20 nutrient mix especially if supplemented with protein powder.

Summary

Whatever we choose when we are carrying emergency rations for ourselves when playing in remote areas or in preparation for dealing with cold, tired and hungry casualties, a little thought can yield significant improvements in palatability, digestibility, speed of recovery, the longevity of recovery, and morale than simply slinging in an extra bag of M&Ms and crossing your fingers.

References

1. Spring B, Alexander BL. (1989). “Sugar and hyperactivity: Another look”. Pp. 231–249 in Handbook of the Psychophysiology of Human Eating, R.Shepard, editor. , ed. New York: John Wiley.

2. Gonder-Frederick L, Hall JL, VogtJ, Cox DJ, Green J, and Gold PE. (1987). “Memory enhancement in elderly humans: Effects of glucose ingestion”. Physiological Behavior. 41:503–504

3. Spring B, Chiodo J and Bowen D. (1987). “Carbohydrates, tryptophan and behavior: A methodological review”. Psychological Bulletin. 102:234–256

4. Harris S. (1924). “Hyperinsulinism and dysinsulin”. Journal of the American Medical Association. 83:729–733.

5. Dufty W. (1975). Sugar Blues. New York: Warner Books.

6. Permuth MA. (1976). “Postprandial hypoglycemia”. Diabetic Care. 25:719–733

7. Spring BJ. Pingitore R. Schoenfeld J. (1994) “Carbohydrates, Protein and Performance.” in Enhancing Food Components for Operational Rations: Food Components to Enhance Performance: An Evaluation of Potential Performance Institute of Medicine (US) Committee on Military Nutrition Research. Marriott BM (Ed.). Washington (DC): National Academies Press (US). Ch17,

8. Qamar MI, Read AE. (1988) “Effects of ingestion of carbohydrate, fat, protein, and water on the mesenteric blood flow in man”. Scandinavian Journal of Gastroenterol. Jan;23(1):26-30

9. Eberle SG. (2013) Endurance sports nutrition. Human Kinetics.

10. American College of Sports Medicine; American Dietetic Association; Dietitians of Canada. (2000) “Joint Position Statement: nutrition and athletic performance. American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada”. Medicine and Science in Sports and Exercise. Dec;32(12):2130-45

11. American Dietetic Association, Dietitians of Canada, American College of Sports Medicine, et al. (2009) “American College of Sports Medicine position stand. Nutrition and athletic performance”. Medicine and Science in Sports and Exercise. Mar;41(3):709-731

12. Palmer H, Graham G, Williams K, Day RA (2010) “Risk-benefit assessment of paracetamol (acetaminophen) combined with caffeine”. Pain Medicine. un;11(6):951-65

13. Derry CJ, Derry S, Moore RA. (2014) “Caffeine as an analgesic adjuvant for acute pain in adults”. Cochrane Database Systematic Review. Dec 11;2014(12)

14. Welsh EJ, Bara A, Barley E, Cates CJ. (2010) “Caffeine for asthma”. Cochrane Database Systematic Review. Jan 20;2010(1)

15. Verma R, Huang Z, Deutschman CS, Levy RJ. (2009) “Caffeine restores myocardial cytochrome oxidase activity and improves cardiac function during sepsis”. Critical Care Medicine. Apr;37(4):1397-402.