Essentials of Nutrition for Sports

Subjects were fed carbohydrate at the rate of 0.8 grams per
kilogram per hour, every 30 minutes, for 5 hours.

For example, a 70-kilogram, 154-pound subject would have

received 28 grams (112 calories) of carbohydrate every 30 minutes.

On another occasion, in addition to receiving the same amount of

carbohydrate, protein was added in the amount of 0.4 grams per kilogram per hour (0.2 grams per kilogram every 30 minutes).

For example, a 70-kilogram, 154-pound subject would have

received 28 grams (112 calories) of carbohydrate and 14 grams (56 calories) of protein every 30 minutes.

Synthesis of muscle glycogen was the endpoint. Protein helped, as is dramatically illustrated in

Figure 7

, taken

from the study. This group fared much better when receiving carbohydrate and protein than when given carbohydrate alone.

Figure 7. van Loon et al. AJCN 72(1) 106. Half-truth. Carbohydrate and protein

were shown to result in more

glycogen synthesis than carbohydrate alone.

Figure 7

was widely reproduced, for example, on commercial

websites promoting Endurox R4.

The full truth is that researcher van Loon examined the group a

third time.

Instead of adding protein, though, this third time the group

received additional carbohydrate. The additional carbohydrate, 0.4 grams per kilogram, was the same amount calorically as the additional protein received by the group when protein was added.

For example, a 70-kilogram, 154-pound subject would have

received 42 grams (168 calories) of carbohydrate every 30 minutes.

With additional carbohydrate, the subjects did the best. That is to say when the amount of calories given was the same,

carbohydrate worked better than a mixture of carbohydrate and protein. This is illustrated in

Figure 8

.

Figure 8. van Loon et al. AJCN 72(1) 106. Full-truth. Carbohydrate given in equal caloric amounts to carbohydrate and protein were shown to result in greater glycogen synthesis than carbohydrate and protein.

Nutrition for Sports, Essentials of 68