Diet, nutrition and the prevention of excess weight gain and obesity

Objective: To review the evidence on the diet and nutrition causes of obesity and to recommend strategies to reduce obesity prevalence.
Design: The evidence for potential aetiological factors and strategies to reduce obesity prevalence was reviewed, and recommendations for public health action, population nutrition goals and further research were made.
Results: Protective factors against obesity were considered to be: regular physical activity (convincing); a high intake of dietary non-starch polysaccharides (NSP)/fibre (convincing); supportive home and school environments for children (probable); and breastfeeding (probable). Risk factors for obesity were considered to be sedentary lifestyles (convincing); a high intake of energy-dense, micronutrient-poor foods (convincing); heavy marketing of energy-dense foods and fast food outlets (probable); sugar-sweetened soft drinks and fruit juices (probable); adverse social and economic conditions—developed countries, especially in women (probable).
A broad range of strategies were recommended to reduce obesity prevalence including: influencing the food supply to make healthy choices easier; reducing the marketing of energy dense foods and beverages to children; influencing urban environments and transport systems to promote physical activity; developing community-wide programmes in multiple settings; increased communications about healthy eating and physical activity; and improved health services to promote breastfeeding and manage currently overweight or obese people.
Conclusions: The increasing prevalence of obesity is a major health threat in both low- and high income countries. Comprehensive programmes will be needed to turn the epidemic around.

The medical provision of hydration and nutrition: Two very different outcomes in Victoria and Florida

Decisions to withhold or withdraw medical hydration and nutrition are amongst the most difficult that confront patients and their families, medical
and other health professionals all over the world. This article discusses two cases relating to lawful withdrawal and withholding of a percutaneous endoscopic gastrostomy tube (PEG) from incompetent patients with no hope of recovery. Victoria and Florida have statutory frameworks that provide for advance directives, however in both Gardner; Re BWV and Schindler v Schiavo; Re Scliiavo the respective patients did not leave documented instructions. The article analyses the two cases and their outcomes from legal, medical and ethical perspectives.

The effect of exercise and nutrition on the mechanostat

In this review, we discuss the effect of increased and decreased loading and nutrition deficiency on muscle and bone mass and strength (and bone length and architecture) independently and combined. Both exercise and nutrition are integral components of the mechanostat model but both have distinctly different roles. Mechanical strain imparted by muscle action is responsible for the development of the external size and shape of the bone and subsequently the bone strength. In contrast, immobilization during growth results in reduced growth in bone length and a loss of bone strength due to large losses in bone mass (a result of endosteal resorption in cortical bone and trabecular thinning) and changes in geometry (bone shafts do not develop their characteristic shape but rather develop a rounded default shape). The use of surrogate measures for peak muscle forces acting on bone (muscle strength, size, or mass) limits our ability to confirm a cause-and-effect relationship between peak muscle force acting on bone and changes in bone strength. However, the examples presented in this review support the notion that under adequate nutrition, exercise has the potential to increase peak muscle forces acting on bone and thus can lead to a proportional increase in bone strength. In contrast, nutrition alone does not influence muscle or bone in a dose-dependent manner. Muscle and bone are only influenced when there is nutritional deficiency – and in this case the effect is profound. Similar to immobilization, the immediate effect of malnutrition is a reduction in longitudinal growth. More specifically, protein and energy malnutrition results in massive bone loss due to endosteal resorption in cortical bone and trabecular thinning. Unlike loading however, there is indirect evidence that severe malnutrition when associated with menstrual dysfunction can shift the mechanostat set point upward, thus leading to less bone accrual for a given amount of bone strain.

Understanding environmental influences on nutrition and physical activity behaviors: where should we look and what should we count?

Research interest in the influence of environmental factors on nutrition and physical activity behaviors has surged internationally in recent years. This is evident from a rapidly expanding literature and facilitated by advances in methodological and analytical approaches to assessing multiple levels of influence on health behaviors. However, a number of conceptual challenges complicate research endeavours in this field. The purpose of this paper is to provide a 'state of the science' overview of evidence regarding environmental influences on nutrition and physical activity behaviors. We focus particularly on a number of key conceptual and methodological issues, including: a consideration of how the environment is defined; the selection and operationalization of environmental exposures; and the importance of integrating existing understanding of individual influences on behavior with the emerging data on the role of the environment. We draw on examples from the published literature including our own research studies to illustrate these issues. We conclude by proposing a research agenda to progress understanding of the influences of the environment on population nutrition and physical activity behaviors.

Nest-tree selection by the threatened brush-tailed phascogale (phascogale tapoatafa) (marsupialia: dasyuridae) in a highly fragmented agricultural landscape

The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual’s home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

Evaluation of a brief pilot nutrition and exercise intervention for the prevention of weight gain in general practice patients

Objective To pilot-test a brief written prescription recommending lifestyle changes delivered by general practitioners (GPs) to their patients.

Design The Active Nutrition Script (ANS) included five nutrition messages and personalised exercise advice for a healthy lifestyle and/or the prevention of weight gain. GPs were asked to administer 10 scripts over 4 weeks to 10 adult patients with a body mass index (BMI) of between 23 and 30 kg m− 2. Information recorded on the script consisted of patients' weight, height, waist circumference, gender and date of birth, type and frequency of physical activity prescribed, and the selected nutrition messages. GPs also recorded reasons for administering the script. Interviews recorded GPs views on using the script.

Setting General practices located across greater Melbourne.

Subjects and results Nineteen GPs (63% female) provided a median of nine scripts over 4 weeks. Scripts were administered to 145 patients (mean age: 54 ± 13.2 years, mean BMI: 31.7 ± 6.3 kg m− 2; 57% female), 52% of whom were classified as obese (BMI >30 kg m− 2). GPs cited ‘weight reduction’ as a reason for writing the script for 78% of patients. All interviewed GPs (90%, n = 17) indicated that the messages were clear and simple to deliver.

Conclusions GPs found the ANS provided clear nutrition messages that were simple to deliver. However, GPs administered the script to obese patients for weight loss rather than to prevent weight gain among the target group. This has important implications for future health promotion interventions designed for general practice.

In the shadow of the volcanoes: the impact of intervention on the nutrition and health status of Rwandan refugee children in Zaire two years from the exodus

Objective: To evaluate the public health and nutritional situation of refugee children in Katale camp, Eastern Zaire, after two years of nutritional and health intervention from 1994 to 1996.
Design: Cross-sectional survey using a two-stage cluster sampling method. Anthropometric data were collected from 28 May 1996 to 4 June 1996. Retrospective review of food basket monitoring data over the preceding six months and the United Nations High Commission for Refugees' weekly mortality data was conducted. Measles immunisation coverage data were surveyed simultaneously, using child health records.
Main outcome measures: Nutritional status measured by weight-for-height index (W/H), measles immunisation status, average daily energy content of the general food ration and crude mortality rate.
Setting: Katale refugee camp, Zaire, June 1996.
Analysis: Weight-for-height index and proportion of immunised children were computed using EPINUT, part of EPINFO computer package.
Results: Malnutrition was found to be most prevalent in children aged six to 29 months old (W/H < -2 Z-score and/or oedema: 6.2%; 95% CI: 3.4%, 10.6%), among whom the malnutrition rate was almost double the overall malnutrition prevalence (W/H < -2 Z-score and/or oedema: 3.5% (95% CI: 1.5%, 7.2%). The general food ration, although conforming to the World Food Program minimum standards of adequacy in terms of variety (being composed of cereals, oil, beans, blended cereal and legume mixes and salt), provided only 6240 kJ on average (95% CI: 5040, 7140 kJ) per person per day, thus meeting only 57% to 84% of the minimum energy requirements for an adult, and falling well below the needs for sub groups with higher nutritional requirements such as children, pregnant and breastfeeding women and the sick. Measles immunisation coverage in children nine to 59 months was 88.6%. The crude mortality rate was found to be 0.3 per 10 000 per day. Refugees received 15 litres of clean water per person per day.
Conclusion: Public health interventions in Katale camp 1994 to 1996 had reduced mortality and morbidity rates dramatically. This was not reflected in the malnutrition rates for children under five years, that remained stable after an initial fall despite two years of nutritional intervention. The factors contributed to this were related to an inadequate general food ration (due to food shortages), lack of ability to supplement the diet, (due to economic restrictions that were imposed in the camp) and inequities in the food distribution process (due to food being siphoned off by camp leaders for military purposes).

A general rooted tree drawing algorithm

A general rooted tree drawing algorithm is designed in this paper. It satisfies the basic aesthetic criteria and can be well applied to binary trees. Given an area, any complex tree can be drawn within the area in users' favorite styles. The algorithm is efficient with O(LxNxlogN) time complexity and self-adaptive as well.

Migrants getting fat in Australia: acculturation and its effects on the nutrition and physical activity of African migrants to developed countries

Obesity is a significant health problem in Australia and other developed countries and acculturation is one fo the many risk factors. This new book summarizes acculturation and anthropometric outcomes among sub-Saharan African migrants in Australia. The book further examines the relationship between acculturation and food, energy and nutrient intake and physical activity. Some policy recommendations are proposed.