Intakes of High Fat and High Carbohydrate Foods by Humans Increased with Exposure to Increasing Altitude During an Expedition to Mt. Everest

Abstract

The objectives of the study were to determine total energy intakes, distribution of energy derived from the macronutrients, and the effects of increasing altitudes on energy and macronutrient consumption during exposure to high altitudes. High fat, low carbohydrate diets (35% and 50% of energy, respectively) or low fat, high carbohydrate diets (20% and 65% of energy, respectively) were provided to two groups of subjects for a 3-wk period. Groups then consumed the alternate diet for 3 wk, followed by a return to the original diet for the remaining 3 wk of the study. Free choice of individual items and amounts within each diet was permitted. Intake of food and fluid was determined by means of monitored entries in daily food records. Five subjects remained at Base Camp (5300 m) and 10 subjects climbed to altitudes up to and including the summit of Mt. Everest (8848 m). Subjects consumed an average of 10.22 +/- 4.57 MJ/d (2442 +/- 1092 kcal) energy while at Base Camp, with climbers consuming significantly more than Base Camp personnel [11.89 +/- 4. 88 vs. 7.87 +/- 2.98 MJ/d (2841 +/- 1167 vs. 1881 +/- 713 kcal/d), P </= 0.0001]. There was a significant decline in energy consumption at increasing altitudes (P = 0.022), but no shift in distribution of energy provided from fat, carbohydrate or protein (P > 0.05). Contrary to previous reports, subjects in this study did not shift their food selections away from the high fat items towards high carbohydrate items.

Energy at High Altitude

“…In terms of macronutrient provision, some evidence suggests that a preference for meals high in carbohydrate occurs at HA [37] while another study showed climbers preferentially chose highfat diets [62]. Fat is the most energy dense macronutrient (an important consideration in the development of ration packs), but yields less energy per unit oxygen consumed when compared to carbohydrate (4.69 kcal l -1 vs. 5.05 kcal l -1 ) a highly relevant fact in the oxygen-poor environment of HA [63].…”

Nutrição para os praticantes de exercício em grandes altitudes

“…Um estudo que avaliou o consumo dos diferentes macronutrientes em altitudes crescentes, entretanto, demonstrou uma tendência de aumento no consumo tanto de alimentos ricos em carboidrato como de alimentos ricos em gordura 37 . O mais recomendável, então, seria não excluir alimentos saborosos ricos em gordura, já que são fontes ricas em energia, que podem ajudar no fornecimento da necessidade energética aumentada na altitude.…”

“…O mais recomendável, então, seria não excluir alimentos saborosos ricos em gordura, já que são fontes ricas em energia, que podem ajudar no fornecimento da necessidade energética aumentada na altitude. Queijo, peixes enlatados em óleo, chocolate, entre outros, preenchem os critérios de alimentos ricos em gordura, que são facilmente preparados para o consumo 37 .…”

Nutritional Strategies for the Preservation of Fat Free Mass at High Altitude

“…A number of explanations have been proposed including anorexia, elevated basal metabolic rate, body water loss, and altered satiety hormones. However, the majority of studies support that altitude-induced weight loss is largely a function of negative energy balance secondary to inadequate energy intake [1,2,3,4,5,6,7,8,9]. Energy expenditure is elevated at altitude and is equivalent to moderate to high intensity exercise conducted at sea level [3].…”

“…Energy expenditure is elevated at altitude and is equivalent to moderate to high intensity exercise conducted at sea level [3]. When this energy expenditure is combined with suboptimal energy intakes of 50%–70% of daily requirements weight loss occurs [1,2,3,4,5,6,7,8,9]. …”