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I . In three separate experiments, four groups of five to eight young male rats were fed either (i) a high-protein diet, for which the net dietaryprotein : totalmetabolizableenergyratio ( N D~ : E) was 0.1 (HP diet); or (ii) a low-protein diet, for which N D~: E was 0.04 (LP diet). In both these groups, food intake was ad lib. In group (iii) the HP diet was given in an amount approximately equal to that taken by the LP group fed ad lib. (HP-restricted). In group (iv) rats were fasted for 48 h after receiving the H P diet (HP-fasted). Each experiment lasted 4 weeks.2. In the LP and HP-restricted groups, food intake was about 50% of that of the HP rats, while body-weight, after 4 weeks on diet was about 35 % and 5 5 yo of that of HP rats, for L P and HP-restricted respectively. Both groups of malnourished rats gained some weight during the experiment. 3. Measurements of oral glucose tolerance and plasma insulin levels were made in the fourth week. LP and HP-restricted rats both showed low fasting insulin levels and low insulin to glucose ratios during the glucose tolerance tests; the LP rats were more seriously affected.4. At the end of the fourth week the rats were killed and blood, liver and gastrocnemius muscle were analysed. LP rats showed specifically and consistently low values for haemoglobin and plasma protein concentration, and low activities of hepatic glucose-6-phosphatase (EC 3 , I . 3.9) and of alanine aminotransferase (EC 2.6. I . 2) in liver and muscle. The activity of hepatic aspartate aminotransferase (ECz. 6. I . I ) was, if anything, increased. The plasma amino acid concentrations and ratios showed a specific fall in branched-chain amino acids. Liver fat concentration was consistently elevated. The HP-restricted rats had normal values for haemoglobin, plasma protein and liver fat, and near-normal values for plasma amino acids. Hepatic alanine aminotransferase showed increased activity compared with H P rats, but muscle alanine aminotransferase showed reduced activity. The HP-fasted rats had increased haemoglobin, plasma protein and liver fat concentration, and very low liver glycogen concentrations. Hepatic alanine aminotransferase activity was elevated. Plasma alanine concentration was specifically reduced. .The results are consistent with suppression of gluconeogenesis, liver dysfunction and essential amino aciddeprivation in LP rats. These biochemical changes found in rats on a low intake of a diet of low proteinand high carbohydratevalue are similar to those found in kwashiorkor. An equally low intake of a diet of good protein value (HP-restricted) led to marginally better growth, accompanied by biochemical signs of increased gluconeogenesis, analogous to those reported for nutritional marasmus. This nutritional state was not biochemically identical with that of acute fasting.6. The results are discussed in terms of the consistency of the rat model, and its contribution to understanding biochemical changes found in infant malnutrition.

Severe protein-calorie deficiency resembling human syndromes (e.g., marasmus and kwashiorkor) has been produced in young pigs by manipulation of dietary protein and carbohydrate levels. These animals show impaired glucose tolerance; increased insulin sensitivity, including hypoglycemia nonresponsiveness; accumulation of glycogen in the liver and deficiency of hepatic glucose-6-phosphatase; normal or raised excretion of urinary corticosteroids. Tissue water content is elevated but fat accumulates only in animals receiving extra carbohydrate. It is suggested that a deficiency of insulin and of thyroid and growth hormones and a consequent relative excess of adrenocortical hormones is characteristic of severe protein-calorie deficiency in humans and experimental animals and explains many of the biochemical changes.

Littermate dogs were fed from weaning on high-protein diets (HP) or on dietswhich were adequate in calories but marginally deficient in protein (LP). The LP animals grew at a slightly retarded rate but showed no other outward abnormality. In the HP animals, intravenous glucose tolerance (K) increased steadily up to twelve months of age (K = 6) and then declined to the adult value (K = 4.7). These changes were accelerated and exaggerated in LP dogs so that, from seven months onwards, the K values for the LP dogs became progressively lower than those of their HP littermates. Although the LP diet was adequate for adult maintenance and other biochemical signs of proteincalorie deficiency were corrected in the adult, glucose tolerance remained impaired (mean K for HP adults = 4.7 and for LP adults = 3.3). In the LP dog decreasing glucose tolerance was associated with increasing resistance to exogenous insulin. During pregnancy, the HP animals showed an early increase in K followed by a progressive fall. The LP animals showed little change in K during pregnancy, but after lactation both glucose tolerance and sensitivity to insulin increased. Pups born to LP mothers showed signs of congenital malnutrition; they also showed greatly enhanced glucose tolerance in early life. Young dogs, whether fed HP or LP diets, showed rapid impairment of glucosetolerance when acutely infected with toxocara canis. The findings for dogs are compared with those reported in human diabetes mellitus.

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Oxygen consumption and thyroid hormone status have been investigated in relation to dietary protein and energy intake in young growing rats fed a control diet of 18% protein as well as diets containing 9 and 4.5% protein fed ad libitum and an 18% protein diet fed at a restricted intake for up to 14 days. Measurements of growth rate, food intake and oxygen consumption indicated that the rats fed a 4.5% protein diet ad libitum and those fed restricted amounts of an 18% protein diet have behaved similarly with severely arrested growth and reduced rates of oxygen consumption and food intake. However, the rats fed the 9% protein diet ad libitum differed from the control group only in terms of a reduced growth rate. Among all the rats thyroid hormone status was associated with the metabolic rate only in the case of the concentration of free L-3,3',5-triiodothyronine (T3), which was reduced in the groups fed 4.5% protein and 18% protein (restricted). Total T3 was actually increased in the rats fed 9% and 4.5% protein and unchanged in the restricted group. These differences in the concentrations of free and total T3 appeared to reflect the fact that the binding capacity for T3 increased with decreasing levels of dietary protein. It is concluded therefore that measurement of free rather than total T3 is the appropriate index of physiological thyroid status in protein-energy malnutrition, at least in the rat.

BackgroundLimited evidence supports a possible association between a person’s perception of their weight status and their quality of life (QoL). This study evaluates whether misperception around weight status is associated with QoL and the impact of gender on this association.MethodsA cross-sectional survey of Australian adults (n = 1,905 analysed) collected self-reported height and weight (used to estimate BMI), gender and QoL (described using the AQoL-8D). Participants reported whether they perceived their weight status to be ‘underweight’, ‘healthy weight’, ‘overweight’ or ‘obese’. Misperception around weight status was categorised based on perceived weight status and self-reported BMI. Ordinary least squares regression was used to test associations between self-reported overall, physical and psychosocial QoL, misperception of weight status, and gender, across different BMI categories, after controlling for income, education, relationship status and health conditions.ResultsCompared to accurate perception, underestimation of weight status was associated with higher overall QoL for obese males and females and for overweight males. Overestimation of weight status was associated with higher overall QoL for underweight females and lower overall QoL for healthy weight males and females. The same pattern was seen for psychosocial QoL. Physical QoL was less sensitive to misperception than psychosocial QoL.ConclusionsSelf-reported misperception around weight status is associated with overall, psychosocial and to a lesser extent physical QoL in Australian adults, although its role depends on BMI category and gender. Generally misperception in the direction of “healthy weight” is associated with higher QoL and overestimation of weight status by those who are of healthy weight is associated with lower QoL. Findings should be confirmed in datasets that contain measured as opposed to self-report height and weight.Electronic supplementary materialThe online version of this article (doi:10.1186/s12955-017-0627-7) contains supplementary material, which is available to authorized users.

Weanling pigs, dogs and rats were fed diets of different protein value. Some dogs and rats remained on the diets through pregnancy, and their offspring were also fed on the experimental diets. Measurements made during the life of the animals included intravenous glucose tolerance, insulin sensitivity, concentrations of growth hormone and insulin in plasma, as well as urinary corticosteroid excretion. The hypophyses, pancreata, thyroids and adrenals were examined histologically. Congenitally malnourished animals, and animals severely malnourished from weaning, showed marked histological changes, especially in the endocrine portion of the pancreas and in the thyroid. However, even a mild deficiency of protein disturbed the endocrine balance and produced marked aberrations in the control of carbohydrate metabolism, which persisted after apparent rehabilitation on a good diet. The experimental findings are discussed in relation to human deficiency syndromes such as marasmus and kwashiorkor.