Evidence of negative energy balance using doubly labelled water in elite Kenyan endurance runners prior to competition

Abstract

Previous studies have found Kenyan endurance runners to be in negative energy balance during training and prior to competition. The aim of the present study was to assess energy balance in nine elite Kenyan endurance runners during heavy training. Energy intake and expenditure were determined over 7 d using weighed dietary intake and doubly labelled water, respectively. Athletes were on average in negative energy balance (mean energy intake 13 241 (SD 1330) kJ/d v. mean energy expenditure 14 611 (SD 1043) kJ/d; P¼0·046), although there was no loss in body mass (mean 56·0 (SD 3·4) kg v. 55·7 (SD 3·6) kg; P¼ 0·285). The calculation of underreporting was 13 % (range 2 24 to þ9 %) and almost entirely accounted for by undereating (9 % (range 2 55 to þ 39 %)) as opposed to a lack of significant underrecording (i.e. total water intake was no different from water loss (mean 4·2 (SD 0·6) l/d v. 4·5 (SD 0·8) l/d; P¼0·496)). Fluid intake was modest and consisted mainly of water (0·9 (SD 0·5) l/d) and milky tea (0·9 (SD 0·3) l/d). The diet was high in carbohydrate (67·3 (SD 7·8) %) and sufficient in protein (15·3 (SD 4·0) %) and fat (17·4 (SD 3·9) %). These results confirm previous observations that Kenyan runners are in negative energy balance during periods of intense training. A negative energy balance would result in a reduction in body mass, which, when combined with a high carbohydrate diet, would have the potential in the short term to enhance endurance running performance by reducing the energy cost of running.Energy expenditure: Doubly labelled water: Energy intake: Undereating: Intense high-altitude training: East African endurance athletes Male Kenyan middle-and long-distance runners have dominated athletics since the 1960s, but until recently diet and nutrition in these athletes had not been comprehensively investigated. The diet of nine elite Kenyan endurance runners was investigated over a 7 d training period 1 week before the Kenyan national cross-country trials (Onywera et al. 2004). Energy intake (EI) was assessed by weighed dietary record and was significantly lower than energy expenditure (EE) as assessed by the physical activity ratio (mean EI 12 486 (SD 1225) kJ/d v. physical activity ratio 15 069 (SD 497) kJ/d), suggesting that the athletes were in negative energy balance prior to competition. The mean difference of 2585 kJ/d between EI and EE accounted precisely for the loss in body mass over the 7 d period (mean body mass 58·9 (SD 2·7) kg v. 58·3 (SD 2·6) kg, where 1 kg was assumed to be equivalent to 30 000 kJ; Westerterp et al. 1995).These results corroborated those of an earlier study evaluating the nutrient intake of Kenyan runners (Mukeshi & Thairu, 1993). The reported EI in that study was low (9781 kJ/d), and considering that the athletes were training intensely, the validity of these results was questioned by the authors of the only other study to have assessed the dietary intake of Kenyan runners (Christensen et al. 2002). Those authors studied twelve adolescent (15-20-year-old) male Kenyan r...

The Assessment of Total Energy Expenditure During a 14-Day In-Season Period of Professional Rugby League Players Using the Doubly Labelled Water Method

“…Previous research has suggested that the self-reported TEI bias can be as high as 34% (Ebine et al, 2000;Fudge et al, 2006;Hill et al, 2002), which appears likely in the present study. These data confirm that caution should be taken when interpreting food diaries from athletes, even when considerable care has been taken by the athlete and the practitioner to complete them accurately.…”

Consumo alimentar e perfil antropométrico de tenistas amadores e profissionais

“…Ambos os processos envolvem componentes perceptivos, emotivos e cognitivos, ainda pouco explorados (30) . O comportamento do sub-relato é comum entre atletas (31)(32)(33)(34) . No estudo de Edwards et al (31) , utilizando o método da água duplamente marcada, foi observado que corredoras apresentam ingestão energética inferior (32%) ao gasto energético.…”

“…Os autores atribuíram o sub-relato ao comportamento de sub-registro, uma vez que o peso dos atletas não sofreu alteração (33) . Já no estudo de Fudge et al (34) também foi observado sub-relato por parte de corredores quenianos que reduzem, propositalmente, a sua ingestão calórica no período que antecede a competição. Entretanto, nesse último estudo (34) o sub-relato foi, principalmente, associado ao subconsumo.…”

Rendimiento excelente en las carreras de larga distancia : estudio comparado de corredores kenianos y españoles de alto rendimiento = Excellent performance in long distance races : high performance kenyan and spanish runners comparative research

“…Apoyando esta afirmación, los dos estudios de corredores kenianos de resistencia (Fudge et al, 2006y Onywera et al, 2004 Las comidas eran básicamente pan, arroz hervido, patata hervida, avena, repollo, alubias rojas y ugali (densa masa de pasta de maíz). La carne (principalmente de ternera) era servida en el campamento cuatro veces por semana y consumida en escasa cantidad (aproximadamente 100 gramos al día), aunque los atletas podían acceder a más carne y a otros alimentos cuando visitaban sus hogares rurales.…”

“…Durante el día también consumían una cantidad significativa de té (con leche). En cuanto a una suplementación alimenticia, los corredores kenianos no tomaban ningún tipo de suplementos (Fudge et al, 2006y Onywera et al, 2004.…”