Här kommer en lång bump. Mina tankar handlar om väldigt lågt intag av kalorier, där folk hävdar att kroppen hamnar i svältläge. Alltså ej total avsaknad av energi. (folk som går i samma PT-kurs)
Citat:
THE EFFECT OF LOWERING THE ENERGY INTAKE ON ENERGY METABOLISM
In the classical Minnesota study of undernutrition (19) the energy intakes of 32 young men were approximately halved for 24 weeks. Body weights fell by 24% but by the end of the experiment had stabilised. The subjects had adapted by reducing energy expenditure as a result of reduced body size, physical activity and metabolic activity. BMR fell by 39%, which was more than the fall in body weight. In terms of per kg active cell mass, they were 16% lower which represents a true metabolic adaptation. One third of the fall in BMR could be explained by reduced metabolic activity and the remainder by reduced body size.
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Menar de att cellernas energiförbrukning minskade med 16% vid väldigt lågt intag av energi?
Hur kan basmetabolismen sänkas? Effektiviseras organens energiförbrukning eller sänks dess aktivitet?
Citat:
The falls in BMR made up a third of the total reduction in energy expenditure. The rest arose from decreased energy expenditure due to physical activity, of which 60% could be explained by reduced volitional activity and 40% by the reduced energy cost of tasks due to the smaller body size. There was no change in the efficiency of physical work. The energy cost of treadmill walking expressed per kg body weight was constant throughout the experiment.
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Den här delen verkar ge svar på mina frågor om jag tolkat det som de skriver korrekt. BMR sänktes till 60% av att de
(volitional =medvetet valde?) att röra på sig mindre och 40% av kroppsmassa? Men det blir 100% och då kan ju inte cellernas energiförbrukning minska pga "svält"?
Citat:
However, the contribution of metabolic adaptation varies according to the duration of undernutrition. Grande and co-workers (20) found that 70% of the reduction in BMR resulting from undernutrition of 2–3 weeks duration could be attributed to reduced metabolic activity and only 30% to reduced cell mass. In chronic undernutrition, all of the reduction in BMR can be attributed to reduced cell mass (21).
The earlier study of undernutrition by Benedict (22) shows similar findings to the Minnesota study but as body composition measurements were unavailable the reasons for the changes in energy expenditure cannot be identified. Benedict concluded, however, that undernutrition caused a decreased net energy cost of walking. As no initial measurements were made the significance of the results depends on to what group they are compared.
Thus, undernutrition of previously normal men can result in a considerable reduction in energy expenditure, mainly by a reduced body size and reduced physical activity. Increased metabolic efficiency makes only a small contribution in medium or long-term undernutrition and there is no firm evidence of an increased mechanical efficiency of work.
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och här säger de om jag har förstått det hela rätt att kaloriunderskottet kan leda mindre energiförbrukning pga lägre fysisk (vardaglig) aktivitet samt att man helt enkelt har en lättare kroppshydda. Samt att i fråga om sänkt energiförbrukning så har cellernas effektivitet (som har med BMR att göra) en mindre (obetydlig i praktiken?) betydelse.
har jag läst studien rätt? sänks den basala ämnesomsättningen såpass mycket att det ger resultat i praktiken?
som sagt.. finns det ett svältläge eller inte i praktiken?