A chronobiological investigation of fitness for work in women on a 220 cal 24 h protein diet.
In a group of nine healthy but obese women a set of tests were used to estimate several physiological and psycho-physiological variables: self-rating of hunger, mood and physical vigor, self-recording of grip-strength, muscular fatigue test, eye-hand skill, tempo, etc. Measurements were performed every 6-hours, at fixed times, during 24-hours, once a week, before (non-restricted spontaneous food intake) and for three weeks on a 220 cal. special protein diet (calcium caseinate: 55g, associated with potassium salts, water and vitamins). Findings relating to the metabolic and hormonal variables while on this diet have already been reported: (a) The diet does not alter the circadian acrophase (peak) of the variables and (b) two distinct metabolic steps occur: first a peak of gluconeogenesis and second, a phase when ketone bodies and fatty acids are used almost exclusively as source of fuel. The present findings show that so long as nitrogen remains in balance this restricted diet (a) does not change the grip strength and the muscular fatigue test; (b) does not alter the mood, the physical vigor etc. and (c) induces a statistically significant fall in "hunger" (self-rating method). We conclude that this low protein diet is compatible with non-strenuous work.
D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm; D004038:Diet, Reducing; D004044:Dietary Proteins / Q000008:administration & dosage*; D004644:Emotions; D005221:Fatigue; D005260:Female; D005943:Gluconeogenesis; D006801:Humans; D006815:Hunger; D009048:Motor Skills; D009765:Obesity / Q000178:diet therapy / Q000503:physiopathology*; D005082:Physical Exertion; D010809:Physical Fitness
D004044:Dietary Proteins