More Food For Thought: Rat Pack Back Chat
Abstract
Chris Forbes-Ewan has twenty-five years’ experience as a Defence nutritionist with the Defence Science and Technology Organisation (DSTO). He is based at DSTO-Scottsdale (aka Defence Nutrition and Food Technology). In this response to an article in the Winter 2010 issue of the Australian Army Journal, Chris argues that, although it is far from perfect, the Combat Ration One Man does make adequate nutrition available for ADF members.
A man’s ration is part of his pay. As we do not pay him in counterfeit money, let us ensure that we do not give him poor food.
- Field Marshall Viscount Slim of Burma
The Winter 2010 issue of Australian Army Journal [Vol. VII, No. 2, pp. 57–66] contained an article by Private Cameron Robison, who is critical of the nutritional quality of ADF combat ration packs (CRP).
Private Robison is to be commended for having the welfare of ADF members at heart. He is correct in noting that CRP do not currently fully satisfy the needs and wants of ADF members. However, his article contains some factual errors. In this article, Private Robison’s claims are compared with results from published DSTO reports and the wider scientific literature.
Energy Requirements Compared to Energy Availability
Private Robison states that ‘A 21-year-old infantry male soldier in the field ... is expected to expend approximately 4000 calories a day.’ (Note: 4000 calories is approximately 16,700 kJ).
This is probably an overestimation—Morrissey et al. reported that Australian soldiers engaged in typical field exercises in jungle and desert environments have mean energy expenditures of a little over 15,000 kJ per man per day.1 The references given by Private Robison for his higher estimate include Kaare Rodahl’s ‘Nutritional Requirements in Cold Climates’. It is correct that soldiers in cold climates will need 10–15 per cent greater energy intake to do the same work as compared to warm climates.2 However, the vast majority of ADF training and operations are conducted in warm climates, so the general-purpose ADF pack—the Combat Ration One Man (CR1M)—provides about 15,500 kJ.3
Private Robison claims that, ‘if a soldier eats every item in an Australian Army CRP ... they will consume approximately 2800 calories.” (Note: 2800 calories is approximately 11,700 kJ). He also states that this is less than the energy provided by rations from several other nations, and that it will lead to negative energy balance (loss of body weight and of body energy reserves) even if soldiers eat all the available food.
As mentioned above, the CR1M provides approximately 15,500 kJ, equal to the average energy expenditure of soldiers studied on two field exercises. Further, it is virtually identical to the average energy provided by the general-purpose ration packs of ten NATO nations involved in a Research Technical Group from 2006 to 2009, in which Australia is also a member.4 If soldiers eat all the food available in the CR1M while engaging in typical field exercises or operations, there will be no serious level of negative energy balance.
Macronutrients (Protein, Fat and Carbohydrate)
Based on an extrapolation from civilian nutritional requirements, Private Robison claims that ADF members on typical operations need ‘about 450g carbohydrates, 150g protein and 110g fat’ per day, and that these macronutrient levels are not available in CRP.
It is not appropriate to scale up macronutrient requirements with increasing energy expenditure. In particular, the need for dietary protein does not increase linearly with energy expenditure. The Australian Institute of Sport recommends that protein intake for endurance (heavy training) should be in the range 1.2–1.6g per kilogram of body weight per day.5 Assuming that soldiers on typical operations are expending energy at similar rates to athletes engaged in heavy training, protein availability in CRP should be in the range 1.2–1.6g per kilogram per day.
... the need for dietary protein does not increase linearly with energy expenditure.
In a recent study, sixty-one infantry soldiers had a mean body weight of 82kg.6 Therefore, it is reasonable to conclude that CRP should provide between 98g and 131g of protein. The CR1M provides about 108g of protein, which is within the recommended range.7
The CR1M also provides nearly 600g of carbohydrate and about 116g of fat.8 These values exceed the minimum requirements suggested by Private Robison for carbohydrate (450g) and fat (110g).
Causes and Effects of CRP Discarding
Private Robison correctly points out that ‘The majority of soldiers do not consume all of the contents of a CRP. The importance of this observation cannot be overemphasised.’ This problem applies not only to ADF CRP, but also to rationing by our NATO allies, and is subject to intensive research in several nations, including Australia.9
Under various tasks, research is being conducted on how food consumption can be increased when troops are fed with CRP. Investigation is also proceeding into how the CRP supply chain may be revised to decrease the time between manufacture of CRP food items and their consumption in the field. Speeding up the process of procuring, packing and distributing CRP would result in troops having access to more acceptable food with a higher retention of vitamins. It would also allow a greater variety of foods to be included in CRP—currently many foods are not potential ration pack items because they do not have sufficient shelf-life (e.g. nuts and many dried fruits). Finally, investigation is being conducted on whether ration packs need to be developed for specific operational situations (e.g. short-term/high-intensity, long-term/low-intensity) and/or specific environmental conditions (e.g. heat, cold, altitude). A prototype hot-weather ration pack has already been field-trialled, and was found to lead to greater consumption in a hot climate than the standard CR1M.10 A prototype pack has also been developed for short-term/high intensity operations.
Sugar and Artificial Sweeteners
Private Robison states that the quantity of sugar provided ‘increases the chance of type 2 diabetes, tooth decay and cancer ... and slows mental and muscular recovery.’
There is no convincing evidence that sugar consumption causes type 2 diabetes. For example, the American Diabetes Association states that ‘the myth that sugar causes diabetes is commonly accepted by many people. Research has shown that it isn’t true ...’.11 Nor is there convincing evidence for an association with cancer. Private Robison is correct when he states that consumption of sugary foods is the main contributor to tooth decay—but with appropriate dental hygiene in the field, this problem should not affect soldiers’ individual readiness. Also, Private Robison (among others) may be pleased to hear that next year’s build of CR1M will include dental chewing gum.
There is no convincing evidence that sugar consumption causes type 2 diabetes.
It is not accurate to claim that sugar ‘slows mental and muscular recovery’. On the contrary, glucose (which constitutes one half of sugar) is the only fuel the brain can use, other than during starvation or semi-starvation. Similarly, repletion of muscle glycogen following exhaustive exercise requires a readily available supply of glucose—sugar performs this role as well as any other food.
It is also stated that ‘another problem with relying on sugar as a fuel source is its quick high, then equally quick low’. This is a condition known as rebound (or reactive) hypoglycaemia. Burke points out that ‘in most cases this is short term and metabolism corrects itself as exercise continues ... Nevertheless, the stigma about eating carbohydrate before exercise persists, and many athletes and coaches talk about “rebound hypoglycaemia” with fear, even though eating carbohydrate could provide extra fuel.’12
Private Robison claims that artificial sweeteners fool the body into believing that sufficient energy has been consumed, and so lead to reduced food intake. He also lists ‘a number of alleged side-effects associated with consumption of artificial sweeteners including bloating, diarrhoea, nausea, skin irritations, wheezing, coughing, chest pains, heart palpitations, anxiety, anger, moods swings and depression’. No references are provided for these claims, so it is difficult to comment on their authenticity. However, it may be relevant to point out that ‘... it is the position of the American Dietetic Association that consumers can safely enjoy a range of nutritive and nonnutritive sweeteners ...’.13 It is also of relevance that only one component—chewing gum—of the CR1M contains artificial sweetener, so soldiers will obtain an insignificant amount of these sweeteners even if they consume the entire CRP.
Salt
Another alleged problem with the CR1M is that it does not provide enough salt: ‘... it is estimated that an average soldier will only eat about 1–1.5g worth of salt from their CRP per day’. This claim is not referenced.
The CR1M actually provides approximately 14g of salt.14 This is more than ten times the salt level estimated by Private Robison to be available in the CR1M. Further, most of this salt is in the food itself, rather than in the salt sachet, so unless the soldier is discarding the vast majority of his food he should obtain adequate salt from the CR1M. For example, soldiers from 1 RAR who took part in a study at Tully in 2008 had a measured consumption of about 6g of salt from CR1M each day.15
Proposed Solutions
Private Robison’s suggested solutions to these perceived problems include extending the range of foods, by adding (for example), ‘salted peanuts, salted cashews, almonds, sunflower seeds and pumpkin seeds’ and ‘mixed nuts’. While this is a good suggestion in theory—and some nuts (e.g. walnuts) may be suitable for inclusion in CRP—because of the current lag time between manufacture and consumption of CRP most of the suggested foods are not suitable ration pack components (they tend to develop rancidity during storage). Another consideration is the relatively high rate of nut allergies in the Australian population; nuts and nut products are not permitted in CRP at present. However, a ‘nut-free’ trail mix is currently undergoing assessment to see if it is suitable for inclusion in the CR1M in future.
Private Robison’s suggested solutions to these perceived problems include extending the range of foods ...
Private Robison also recommends the inclusion of dried fruits in CRP. Although dried fruits are already included in the form of fruit grains in the CR1M, Private Robison’s suggestion that a variety of dried fruits should be available is worthwhile. However, many dried fruits undergo browning and loss of flavour during storage, making them inappropriate components of CRP at present.
If the time between manufacture and consumption of CRP can be substantially shortened, Private Robison’s valuable suggestions may be able to be put into effect—a much wider range of nuts, seeds, dried fruits (and of foods generally) could all be considered for inclusion.
Private Robison recommends including beef jerky in the CR1M. He (and many other soldiers) will be pleased to know that a Beef Steak Bar (similar to beef jerky) has been added to the CR1M. However, because of the time taken for CRP to complete their passage through the supply chain, it will be several years before the Beef Steak Bar will be enjoyed by soldiers in the field.
Private Robison also recommends (appropriately) that a program of nutrition education be conducted and that ‘ideally, this training would be delivered during foundation courses at institutions such as the Army Recruit Training Centre and the Royal Military College’.
The most efficient and effective way in which healthy eating by ADF members can be promoted is being investigated by DSTO under an Army-sponsored task. Nutrition education of recruits at ARTC has been recommended previously,16 while ADF-wide, through-career nutrition education has also been recommended.17 Finally, DSTO is contributing to revision of the Dietary Guidelines for Australians, which will include recommendations for individuals with higher energy requirements (such as endurance athletes and soldiers) and the development of a Military Guide to Healthy Eating.
Conclusion
Private Robison has shown an admirable level of concern about the nutritional status and military preparedness of ADF members who are required to subsist on CRP. Many of his suggestions are worthwhile, and some are in the process of being implemented (or at least investigated further). However, his article does not accurately reflect the current nutritional quality of the CR1M, and the situation is perhaps not quite as dire as he paints it.
This does not mean that ADF CRP are without problems. However, as described above, these problems are being addressed by DSTO in conjunction with Army, DMO, FORCOMD and Joint Logistics.
For general information on Defence nutrition research conducted by DSTO-Scottsdale, I recommend the report by Forbes-Ewan (2009), which is available electronically on the Defence Restricted Intranet at: http://dspace-dsto.dsto.defence.gov.au/dspace/handle/dsto/7391
About the Author
Chris Forbes-Ewan has twenty-five years’ experience in Defence nutrition, including extensive research into food acceptability, food intake, energy expenditure and physical performance enhancement. For ten years he was the Australian National Leader of an international defence technical panel under The Technical Cooperation Program. This panel conducted collaborative and cooperative research into performance enhancement for special and conventional operations. From 2006 to 2009 Chris was the Australian member of a NATO Research Technical Group that developed optimal standards for combat ration packs. Chris is continuing his research into aids to military performance and nutritional promotion of health and military fitness.
Endnotes
1 B L L Morrissey, P J Cavanough, C H Forbes-Ewan and D R Waters, ‘Energy expenditure and food intake of soldiers in three operational environments’, Proceedings of the Nutrition Society, Vol. 15, 1990, p. 241.
2 USARIEM, Nutrition for Health and Performance, Technical Note TN-01/4, United States Army Research Institute of Environmental Medicine, Natick, 2001.
3 RTO Technical Report RTO-TR-HFM-154, Nutrition Science and Food Standards for Military Operations, Final Report of RTO Task Group RTG 154, Research Technical Organisation, North Atlantic Treaty Organization, 2010, Table F-1.
4 Ibid.
5 L Burke, L Bell, M Cort, G Cox, L Farthing, B Greenaway, M Minehan, N Petrunoff and C Wood, Current Concepts in Sports Nutrition, Australian Institute of Sport, Australian Sports Commission, Canberra, 2008.
6 C Kullen, C Booth, J Carins and A Fogarty, ‘Field evaluation of the prototype HWR’, DSTO Technical Report in publication, Department of Defence, Canberra, 2010.
7 RTO Technical Report RTO-TR-HFM-154, Table F-1.
8 Ibid.
9 Ibid, section 3.3.1.1.
10 Kullen, et al, ‘Field evaluation of the prototype HWR’.
11 American Diabetes Association, ‘The Hype about Sugar’, <http://www.diabetes.org/food-and-fitness/food/what-can-i-eat/sweeteners…; accessed 4 August 2010.
12 L Burke, ‘Pre-Event meals: high or low glycemic index foods?’, Sportscience News, May-June 1998, <http://www.sportsci.org/news/compeat/glycemic.html>
13 American Dietetic Association, ‘Position of the American Dietetic Association: Use of Nutritive and Nonnutritive Sweeteners’, Journal of the American Dietetic Association, No. 104, 2004, pp. 255–75.
14 RTO Technical Report RTO-TR-HFM-154, Table F-1.
15 Kullen, et al, ‘Field evaluation of the prototype HWR’.
16 C Forbes-Ewan, ‘Nutritional Enhancement of the Performance of Army Recruits’ unpublished report to 1st Recruit Training Battalion, Defence Nutrition Research Centre, Defence Science and Technology Organisation, 1997; B Skiller, C Booth, R Coad and C Forbes-Ewan, ‘Assessment of Nutritional Status and Fatigue among Army Recruits during the Army Common Recruit Training Course: Part A: Catering Services and Diet’, DSTO-TR-1736, CBRN Defence Centre, Defence Science and Technology Organisation, 2005; C Kullen, J Carins and C Booth, Enhancing Nutrition at ARTC, DSTO-CR-2008-0417, Human Protection and Performance Division, Defence Science and Technology Organisation, 2009.
17 See, for example, C Booth, R Coad, C Forbes-Ewan, G Thomson and P Niro, ‘The Effect of Consumption of Australian Combat Rations on Military Personnel after a Medium-Term Field Exercise’, DSTO-RR-0228, Combatant Protection and Nutrition Branch. Aeronautical and Maritime Research Laboratory, Defence Science and Technology Organisation, 2001.
