Page 103 - Journal of Special Operations Medicine - Winter 2015

acids that the body cannot synthesize on its own) com- preparing and consuming a meal. This generally oc-
position, and digestive and absorptive properties. curs during sustained training and combat operations
19
Some plant-based proteins are also considered high- when SOF are subsisting primarily on combat rations
quality, although it is important to recognize that many or the economy. Consuming supplemental protein may
plant-based proteins provide lower amounts of the es- be an effective measure to maintain adequate protein
sential amino acids compared to animal proteins. intake during operational scenarios. If supplements are
used, they should provide sufficient, but not excessive,
Combining protein sources (i.e., animal and plant amounts of protein (e.g., 20–25g) to maximally stimu-
or various plant proteins together) in a healthy, well- late muscle protein synthesis. Protein supplements are
balanced diet generally provides adequate amounts of often combined with carbohydrate to fuel endurance ex-
the essential amino acids. The amount of protein con- ercise metabolism and, to a lesser amount, fat, which also
sumed at each meal and the timing of those meals also provides energy and improves palatability. This energy-
influence the effectiveness of dietary protein on skele- dense formulation is preferred during sustained military
tal muscle. Distributing daily protein intake as evenly operations. SOF that use supplemental protein during
as possible across meals and snacks will help stimulate periods of relatively low metabolic demand should rec-
muscle protein synthesis (i.e., build muscle) to a greater ognize that consuming supplements without modifying
extent than a more traditional, skewed dietary pattern total dietary intake may contribute to weight gain. 24,25
of protein intake, where 60% or more of daily protein
intake is consumed during one meal (typically dinner). 20 Whey, casein, and soy are among the most common
commercial protein supplements. Whey and casein (i.e.,
Recent studies suggest that consuming a protein- containing the two main proteins found in milk) are considered
snack before bed may also assist with the maintenance of high quality based on their essential amino acid contents
muscle mass by stimulating muscle protein synthesis and and the rate at which they are digested and absorbed.
sparing existing muscle from being degraded to maintain Whey protein is considered a fast protein because it is
blood glucose while sleeping. The amount of protein digested and absorbed quickly, stimulating a robust,
21
that muscle can effectively use to stimulate muscle pro- short-lived (about 2 hours) increase in muscle protein
tein synthesis appears to be 0.25–0.3g/kg of BM per meal, synthesis. Casein is a slowly digested and absorbed pro-
which, for the average man, is about 20–25g per meal. 22,23 tein that results in a lower but more sustained muscle
Consuming protein beyond 0.25–0.3g/kg of BM provides protein synthetic response than whey. For these reasons,
no additional anabolic stimulus; the additional protein is whey protein is often recommended to promote muscle
either used for fuel during periods of high metabolic de- recovery (i.e., synthesis of new and repair of existing
mand or is catabolized and excreted in the urine. Table muscle) after strenuous exercise or sustained physical
2 provides a summary of the protein content of various activity, whereas casein is generally recommended as
whole foods according to particular serving sizes. a pre-bedtime snack to limit endogenous muscle pro-
tein breakdown and stimulate muscle protein synthesis
Protein supplements are recommended when access to while sleeping. 21,26 Soy, a plant-based protein with an
whole foods is limited and time does not permit for essential amino acid, digestive, and absorptive profile

Table 2 Protein Content of Select Foods
Food Serving Size Protein, g Food Serving Size Protein, g
Tuna (canned) 1 can (6 oz) 40 Almonds/most nuts ¼ cup 7
White meat chicken 3 oz cooked 26 Egg 1 large 7
White meat turkey 3 oz cooked 26 Egg whites ¼ cup 7
95% lean ground beef 3 oz cooked 25 Hard cheese 1 oz 7
Pork tenderloin 3 oz cooked 24 Peanut butter 2 TBS 7
Salmon 3 oz cooked 22 American cheese 1 slice (0.75 oz) 6
Greek yogurt 6 oz 17 Bread 1 slice 2
Cottage cheese ½ cup 14 Cold cereal 1 cup 2
Tofu (firm) 4 ounces 10 Vegetables ½ cup 2
Milk or regular yogurt 1 cup (8 oz) 8 Rice, noodles, pasta ½ cup 2
Beans/legumes ½ cup 8 Fruit 1 piece <1

US Military Dietary Protein Recommendations 91