Field Notes Energy Supplement Selection Guide
Numerous energy supplements are available in the marketplace. The use of some supplements is supported by research. The use of others is not. This section is designed to help you select liquid and solid carbohydrate supplements that serve the needs of wildland firefighters.
Sports DrinksThese guidelines are intended to guide the purchase of energy replacement beverages for wildland firefighters. They are based on published studies, field research on firefighters (conducted by MTDC and University of Montana researchers), and on position statements published by the American College of Sports Medicine and the National Athletic Trainers Association.
Recommendation—Firefighters need 1 L of fluid for each hour of work. We recommend that sport drinks comprise one-third to one-half of fluid needs, with the balance supplied by water. That will ensure about 100 kcal of carbohydrate for each hour of work (for example, 1/3 of 300 kcal = 100 kcal/h). Additional carbohydrate can be supplied by solid supplements, such as energy bars.
| Sports Drinks | ||
|---|---|---|
| Guidelines—Consult the nutrition information label found on the product’s package. The information covers the constituents in the mixed or liquid state and is presented per liter of fluid (1 L = 1.0567 qt). Because manufacturers list products for 8, 12, or 16 oz servings, it may be necessary to convert ounces to liters: | ||
| Multiply by | 4.2 to convert an 8-oz serving to liters. 2.8 to convert a 12-oz serving to liters. 2.1 to convert a 16-oz serving to liters. |
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| For 21 g of carbohydrate in a 12-oz serving, multiply 21 g by 2.8 to get grams per liter (21 x 2.8 = 58.8 g/L). | ||
| Serving size | 1 L | |
| Calories per serving | 180 to 320 kcal/L | |
| Carbohydrate | Total | 45 to 80 g/L (4.5 to 8 percent) |
| Carbohydrate | Type | glucose, sucrose, maltose, maltodextrin, or fructose (try to avoid products where fructose or high fructose corn syrup is the first carbohydrate in the list of ingredients) |
| Sodium | 140 to 500 mg/L | |
| Potassium | 80 to 308 mg/L | |
| The following ingredients are not required, either because the ingredient is provided in meals or there is no substantial proof that these ingredients contribute to performance or immune function when they are provided as a supplement. Ephedra, guarana, or other herbal products are not acceptable. Vitamins should not exceed 100 percent of the recommended dietary allowance. | ||
| Protein | 0 to 15 g/L | |
| Magnesium | 0 to 56 mg/L | |
| Vitamin C | 0 to 100 mg/L | |
| Vitamin E | 0 to 160 IU/L (international units per liter) | |
| Sports drinks that meet the specifications include: Advocare Pos-3* All Sport* Cytomax Comp 1 (Arizona Sports Drink) Enervit G* Extran Thirstquencher* G Push** GU20 Gatorade Powerade* Revenge Sport |
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| *High fructose, **High sodium | ||
| A higher carbohydrate concentration (for instance, 10 percent or 100 g/L and 400 kcal/L) can be tolerated after work, when the crew is traveling or awaiting transport. The addition of some protein (a ratio of 1 g of protein for 4 g of carbohydrate) within 2 h after work may reduce muscle stress and accelerate replacement of muscle glycogen. Fruit drinks or colas provide carbohydrate, and solid food snacks can supply additional carbohydrate, protein, and electrolytes. A total of 300 to 500 kcal of carbohydrate energy (liquid and solid) is recommended within 2 h after work. | ||
Energy Bars
These guidelines are intended to guide the purchase of energy bars (solid carbohydrate supplements) for wildland firefighters. They are based on published studies conducted on athletes and military populations, and on field research conducted on wildland firefighters by MTDC and University of Montana researchers. For further information consult the tech tip Feeding the Wildland Firefighter (0251–2323–MTDC, http://www.fs.fed.us/eng/t-d.php?link=pubs/htmlpubs/htm02512323).
Candy Bars?—Some candy bars contain an adequate supply of carbohydrate. However, because candy bars are high in saturated fat, their use should be limited. Candy bars used to provide supplemental carbohydrate should provide at least 30 grams of carbohydrate per serving. While candy bars remain a cost-effective alternative to energy bars, they should not be used to meet more than 25 percent of the solid energy supplement mix (for instance, provide three energy bars for every candy bar).
Recommendation—We recommend that firefighters consume one-third to one-half of an energy or candy bar during each hour of hard work (one-third of a 240-kcal energy bar would be 80 kcal). These solid carbohydrate supplements should be consumed in addition to carbohydrate supplied in fluid-replacement beverages, providing a total of 160 to 240 kcal of supplemental energy for each hour of work.
| Energy Bars | ||
|---|---|---|
| Guidelines—Consult the nutrition information label found on the product’s package. All specifications are listed in units per serving (for instance, calories per energy bar). Each bar constitutes one serving. | ||
| Amount per serving | One energy or candy bar | |
| Calories per serving | 200 to 300 kcal per bar | |
| Carbohydrate | Total | 40 to 70 g |
| Carbohydrate | Type | glucose, sucrose, maltose, maltodextrin, or fructose |
| The following ingredients are not required, either because the ingredient is provided in meals or there is no substantial proof that the ingredient contributes to performance or immune function when it is provided as a supplement. Avoid paying more for ingredients that have not been proven effective. Ephedra, guarana, or other herbal products are not acceptable. | ||
| Protein | up to 15 g (1 g protein per 4 g of carbohydrate) | |
| Fat | Should not exceed 25 percent of total calories | |
| Sodium: | Should not exceed 500 mg per bar | |
| Potassium: | Should not exceed 308 mg per bar | |
| Vitamins: | Should not exceed 100 percent of the recommended dietary allowance | |
| Minerals: | Should not exceed 100 percent of the recommended dietary allowance | |
| The addition of some protein (1 g of protein per 4 g of carbohydrate, with a total of 300 to 500 kcal of carbohydrate consumed) within 2 h after work may reduce muscle stress and accelerate replacement of muscle glycogen. Other solid food snacks can supply some protein. Liquid supplements can provide additional carbohydrate energy and electrolytes to improve fluid retention. | ||
| Energy bars that meet the specifications include: | ||
| Cliff Bar Gatorade Bar Harvest Bar Power Bar |
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| A number of other energy bars meet most of the specifications. | ||
