This proposal is designed to test the protein leverage hypothesis (PLH) in humans: the idea that the level of food consumption in humans, like other animals, is adjusted to maintain a target protein intake. As the prevalence of overweight and obesity increases, with its attendant health problems, the need to identify which dietary components limit rather than exacerbate energy intake is imperative. According to the PLH, the consumption of a diet low in % protein and high in % fat and carbohydrat ....This proposal is designed to test the protein leverage hypothesis (PLH) in humans: the idea that the level of food consumption in humans, like other animals, is adjusted to maintain a target protein intake. As the prevalence of overweight and obesity increases, with its attendant health problems, the need to identify which dietary components limit rather than exacerbate energy intake is imperative. According to the PLH, the consumption of a diet low in % protein and high in % fat and carbohydrate, typical of many Western countries, inevitably requires the ingestion of additional energy to maintain protein intake constant, thus driving weight gain. Conversely, the consumption of a diet that is relatively high in % protein requires the ingestion of lower levels of energy, creating the potential for weight loss. Preliminary experimental and population-level nutritional survey data support the PLH, as does the finding that protein is more satiating than other macronutrients. If, as predicted, small changes in the proportion of protein in diets described in the current study are found to impact on total energy intake there will be significant implications for weight control strategies. Thus, if the PLH is confirmed, public health dietary recommendations and government policy settings for the food industry will need to change. Large-scale intervention studies aimed at demonstrating the longer term impact on body weight will also be required.Read moreRead less
An RCT To Promote Healthy Lifestyle Behaviours From Infancy: An Intervention To Prevent Childhood Overweight
Funder
National Health and Medical Research Council
Funding Amount
$578,631.00
Summary
In Australia, one in four school-aged children is currently overweight and childhood obesity rates are continuing to rise. In the last five years it has become clear that rates of overweight and obesity are also rapidly increasing in pre-school age children. These are issues that are of concern to health officials as well as to parents. We understand that these rising rates in fatness relate to children's diet and activity patterns, and that these patterns, once established are likely to be patt ....In Australia, one in four school-aged children is currently overweight and childhood obesity rates are continuing to rise. In the last five years it has become clear that rates of overweight and obesity are also rapidly increasing in pre-school age children. These are issues that are of concern to health officials as well as to parents. We understand that these rising rates in fatness relate to children's diet and activity patterns, and that these patterns, once established are likely to be patterns for life. To date, there has been relatively little research regarding the chance to support parents to establish the eating and activity patterns that will protect their children from the very beginning of life. This project seeks to support first-time parents to establish healthy eating and activity behaviours in their children using the highly utilised Maternal and Child Health Centres first time parents' groups. We believe that these groups will provide a strongly supportive environment in which to provide parents with strategies and knowledge for promoting healthy eating and activity patterns for their children, and in turn, promote healthy weight gain. This project will assess the effectiveness of this intervention.Read moreRead less
Effects Of The Fatty Acid, Lauric Acid, On Energy Intake And Gut Motor And Hormonal Function In Health And Obesity
Funder
National Health and Medical Research Council
Funding Amount
$744,645.00
Summary
Obesity is largely due to energy intake exceeding energy expenditure, thus, strategies that reduce energy intake will result in weight loss. We discovered recently that the fatty acid, lauric acid, markedly reduces energy intake. Our studies will determine the effects of lauric acid on energy intake and body weight reduction in obese subjects. The research is a new initiative and explores the potential of lauric acid as a novel, nutrient-based and side-effect free approach to obesity management.
A Novel Lipid Sensitive Kinase And Its Role In Obesity-induced Inflammation And Insulin Resistance.
Funder
National Health and Medical Research Council
Funding Amount
$560,045.00
Summary
It is now apparent that obesity leads to chronic low grade inflammation which results in insulin resistance or pre-diabetes. The mechanisms that link obesity-induced inflammation to insulin resistance are not well understood, but involve lipid oversupply. We have preliminary data identifying that a protein, not known to previously play a role in metabolic diseases, is a critical mediator of lipid-induced inflammation. We will investigate the clinical potential of blocking this protein.
Neurobiological Causes Of Overeating In A Rodent Model - Hedonic Versus Homeostatic Control
Funder
National Health and Medical Research Council
Funding Amount
$431,215.00
Summary
Unlimited access to palatable high fat foods, in conjunction with a sedentary life style, has led to increased obesity. Exactly what mechanisms drive over consumption of energy rich foods and override mechanisms that normally regulate body weight? This project will examine feeding behaviour in rats fed palatable high fat diet, to examine when and how they eat. The contribution of brain chemicals implicated in addiction to this eating, and the impact of withdrawal of food will be examined.
Does Early Overnutrition Differentially Alter Hypothalamic Neuropeptides That Regulate Food Intake In The Rat
Funder
National Health and Medical Research Council
Funding Amount
$346,250.00
Summary
In Australia the incidence of obesity, in particular childhood obesity, is increasing dramatically, and the possible long term consequences of this are of great concern. The brain regulates appetite through a number of chemical transmitters such as neuropeptide Y (NPY) which is present in the brains of mammals and causes increased food intake. The effects of overeating from a young age on these brain transmitters has been largely ignored although this may impact on subsequent eating behaviour. I ....In Australia the incidence of obesity, in particular childhood obesity, is increasing dramatically, and the possible long term consequences of this are of great concern. The brain regulates appetite through a number of chemical transmitters such as neuropeptide Y (NPY) which is present in the brains of mammals and causes increased food intake. The effects of overeating from a young age on these brain transmitters has been largely ignored although this may impact on subsequent eating behaviour. In addition to NPY we will study other transmitters in the brain that have profound effects on appetite, some increasing, and others decreasing, food intake. These may form useful therapeutic targets for new drugs for obesity. Key targets we will study include melanocortins, glucagon-like peptide 1, urocortin, melanin concentrating hormone, agouti related peptide, and NPY. We will determine whether overnutrition from birth to weaning leads to changes in these appetite regulating neurotransmitters in the brain, and monitor the hormonal signals that impact on their activity. We will also determine whether early overnutrition exacerbates the subsequent responses to a high fat diet by comparison with rats made obese as adults. We will measure brain concentrations of the neurotransmitters, the amount released from the brain, and determine whether the feeding responses to injections of these agents is altered in obese animals. We have evidence that these transmitters interact in a co-ordinated fashion to affect feeding; this project will examine whether these interactions are maintained in the various types of obesity. Rats are commonly used for this type of study as the processes regulating feeding are very similar to those in humans and these agents cause similar effects in rats and humans. It is hoped that this information will provide new insight into the way brain adapts to overnutrition, and provide potential treatments for obesity and other feeding disorders.Read moreRead less
Assessing Sustainability Of Positive Outcomes In A Successful Child Obesity Prevention Intervention: Follow-up Of The Melbourne InFANT Program
Funder
National Health and Medical Research Council
Funding Amount
$882,700.00
Summary
Early intervention may be the most sustainable and effective means of preventing obesity and promoting healthy lifestyle behaviours (obesity preventive behaviours) including diet, physical activity and reduced sedentary behaviours. This project aims to assess whether differences observed between intervention and control groups at the conclusion of a successful obesity prevention program, the Melbourne InFANT Program, (child aged 18-months) are maintained across the important early childhood year ....Early intervention may be the most sustainable and effective means of preventing obesity and promoting healthy lifestyle behaviours (obesity preventive behaviours) including diet, physical activity and reduced sedentary behaviours. This project aims to assess whether differences observed between intervention and control groups at the conclusion of a successful obesity prevention program, the Melbourne InFANT Program, (child aged 18-months) are maintained across the important early childhood years, to 3.5 and 5 years of age.Read moreRead less
The Nutritional Geometry Of Ageing In A Rodent Model
Funder
National Health and Medical Research Council
Funding Amount
$979,269.00
Summary
A central belief in ageing research is that eating fewer calories prolongs life, and that the source of calories (carbohydrate, fat or protein) is irrelevant. However, a critical assessment indicates that this conclusion is premature. We will use recent techniques in nutrition to define for the first time in mammals the relationship between diet and ageing in a normal and a prematurely ageing strain of mice. The project will provide a novel nutritional approach for promoting healthy ageing.
The Role Of Adipokines In Modulation Of Gastric Vagal Afferent Satiety Signals
Funder
National Health and Medical Research Council
Funding Amount
$624,535.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals are disordered in obesity and may be influenced by factors released from fat stores in the body. The aim of this project is to determine how these factors interact with gastric nerve satiety signals and thus identify targets for the pharmacological treatment of obesity.
The Role Of Arousal And Diaphragm Displacement In The Pathogenesis Of Obstructive Sleep Apnoea
Funder
National Health and Medical Research Council
Funding Amount
$410,875.00
Summary
Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is ....Obstructive sleep apnea (OSA) affects 4% of men and causes excessive daytime sleepiness leading to increased accidents, high blood pressure and premature cardiovascular disease e.g. heart attacks and strokes. OSA is characterized by repetitive obstructions of the floppy portion of the throat during sleep with adverse effects on oxygen levels and sleep quality. OSA is strongly associated with obesity and is 2-3 times more common in men than women. How obesity and male gender predispose to OSA is not known. We will investigate two factors that we believe are most likely involved in causing and explaining this gender difference in OSA. We will examine if breathing responses with brief awakening are sufficient to promote OSA patterns of breathing in snorers and if they are greater in male than female OSA patients. We have already shown that healthy men have greater breathing response to arousal compared to women. These brief arousals occur hundreds of times a night in OSA patients, and over-breathing on arousal may increase the probability of upper airway obstruction on falling back to sleep. We will also investigate why even healthy men show greater breathing responses compared to women. Men tend to accumulate fat centrally, particularly in the abdomen, whereas in women fat tends to be distributed more to the hips and thighs. This could be very important in OSA because downward pull exerted on the upper airway by the diaphragm is likely to be reduced in people with more abdominal obesity. This mechanisms has not yet been studied in humans. We will therefore investigate if increased forces placed on the diaphragm during sleep make the upper airway more prone to collapse. We will also investigate these effects during sleep onset, when there may well be important changes in diaphragm position as muscles relax.Read moreRead less