The mechanisms that balance food intake and energy expenditure determine who will be obese and who will be lean. One of the molecules that regulates energy balance in the mouse is the obese (ob) gene. Mutation of ob results in profound obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. The ob gene product may function as part of a signalling pathway from adipose tissue that acts to regulate the size of the body fat depot.

Positional cloning of the mouse obese gene and its human homologue

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics-European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as 'presarcopenia', 'sarcopenia' and 'severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.

/pdf/sarcopenia-european-consensus-on-definition-and-diagnosis-2axty2moc3.pdf

Sarcopenia: European consensus on definition and diagnosis Report of the European Working Group on Sarcopenia in Older People

Summary: In 1995 the American College of Sports Medicine and the Centers for Disease Control and Prevention published national guidelines on Physical Activity and Public Health. The Committee on Exercise and Cardiac Rehabilitation of the American Heart Association endorsed and supported these recommendations. The purpose of the present report is to update and clarify the 1995 recommendations on the types and amounts of physical activity needed by healthy adults to improve and maintain health. Development of this document was by an expert panel of scientists, including physicians, epidemiologists, exercise scientists, and public health specialists. This panel reviewed advances in pertinent physiologic, epidemiologic, and clinical scientific data, including primary research articles and reviews published since the original recommendation was issued in 1995. Issues considered by the panel included new scientific evidence relating physical activity to health, physical activity recommendations by various organizations in the interim, and communications issues. Key points related to updating the physical activity recommendation were outlined and writing groups were formed. A draft manuscript was prepared and circulated for review to the expert panel as well as to outside experts. Comments were integrated into the final recommendation.

Primary Recommendation: To promote and maintain health, all healthy adults aged 18 to 65 yr need moderate-intensity aerobic (endurance) physical activity for a minimum of 30 min on five days each week or vigorous-intensity aerobic physical activity for a minimum of 20 min on three days each week. [I (A)] Combinations of moderate- and vigorous-intensity activity can be performed to meet this recommendation. [IIa (B)] For example, a person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 min on two other days. Moderate-intensity aerobic activity, which is generally equivalent to a brisk walk and noticeably accelerates the heart rate, can be accumulated toward the 30-min minimum by performing bouts each lasting 10 or more minutes. [I (B)] Vigorous-intensity activity is exemplified by jogging, and causes rapid breathing and a substantial increase in heart rate. In addition, every adult should perform activities that maintain or increase muscular strength and endurance a minimum of two days each week. [IIa (A)] Because of the dose-response relation between physical activity and health, persons who wish to further improve their personal fitness, reduce their risk for chronic diseases and disabilities or prevent unhealthy weight gain may benefit by exceeding the minimum recommended amounts of physical activity. [I (A)]

Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association.

Ten per cent of the world’s school-aged children are estimated to be carrying excess body fat (Fig. 1), with an increased risk for developing chronic disease. Of these overweight children, a quarter are obese, with a significant likelihood of some having multiple risk factors for type 2 diabetes, heart disease and a variety of other co-morbidities before or during early adulthood. The prevalence of overweight is dramatically higher in economically developed regions, but is rising significantly in most parts of the world. In many countries the problem of childhood obesity is worsening at a dramatic rate. Surveys during the 1990s show that in Brazil and the USA, an additional 0.5% of the entire child population became overweight each year. In Canada, Australia and parts of Europe the rates were higher, with an additional 1% of all children becoming overweight each year. The burden upon the health services cannot yet be estimated. Although childhood obesity brings a number of additional problems in its train – hyperinsulinaemia, poor glucose tolerance and a raised risk of type 2 diabetes, hypertension, sleep apnoea, social exclusion and depression – the greatest health problems will be seen in the next generation of adults as the present childhood obesity epidemic passes through to adulthood. Greatly increased rates of heart disease, diabetes, certain cancers, gall bladder disease, osteoarthritis, endocrine disorders and other obesityrelated conditions will be found in young adult populations, and their need for medical treatment may last for their remaining life-times. The costs to the health services, the losses to society and the burdens carried by the individuals involved will be great. The present report has been written to focus attention on the issue and to urge policy-makers to consider taking action before it is too late. Specifically, the report:

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-789X.2004.00133.x

Obesity in children and young people: a crisis in public health.

Targeted disruption of the melanocortin-4 receptor results in obesity in mice

Meal size as a determinant of food intake in normal and hypothalamic obese rats

Effects of alloxan induced diabetes on the feeding patterns of rats.

To investigate the role of glucose utilization in the short-term control of food intake, rats with chronic aortal catheters were either infused continuously with glucose or received glucose infusions concomitant to spontaneous meals for periods averaging 2 days During equivalent control periods 09% NaCl was infused Meal-taking behavior during glucose infusions did not differ from that observed when saline was infused Analysis of blood glucose indicates that the infused glucose was utilized

Absence of effect of intraaortal glucose infusions upon spontaneous meals of rats.

THE regulation of energy intake both in the growing and in the adult animal is one of the most important physiological regulations. The essential characteristics of this regulation in the adult, its precision, sensitivity and accuracy, the individual and strain differences, the differences due to environmental factors (essentially temperature) as well as the alterations in metabolism and body composition correlated with these changes in food intake, have been studied by A. Mayer and his collaborators1. The importance of the integrity of the hypothalamic region of the brain as well as the hyperphagia and resulting obesity due to the hypothalamic lesion have been studied by J. Brobeck and reviewed by him2.

Mechanism of the Regulation of Food Intake

The factors that are hampering the development of practical and acceptable policies in the fields of food and nutrition are examined with particular emphasis on analyzing the disciplinary limitations that prevent physicians nutritionists and economists from working cooperatively with governments to present coherent broad-based plans in these fields. It is assumed in the discussion that the government has determined that adequate nutrition for all people is an appropriate national goal as an alternative to the traditional practice of allowing nutrition status to be secondary to agricultural policy foreign trade health and social policy and economic conditions. Prerequisites for highly centralized direction of all aspects of the food supply do not exist at present in most countries and models for intervention other than adjusting supplies and distribution directly to requirements need to be sought. Recognizing that they cannot control supplies under normal conditions nutritionalists often strive for a utopia in which they control demand. Economists are unwilling to give much attention to those commodities that do not travel through channels of trade or to those commodities that make a considerable contribution to good nutrition but are difficult to quantify. Concerned with nutrition policy the element of civic nutrition education is crucial. The goal of imparting civic nutritional literacy is to enable professionals to become more aware of the nutrition-related issues and to interpret those issues in policy making.

http://science.sciencemag.org/content/sci/188/4188/566.full.pdf

Jean Mayer

Papers

Meal size as a determinant of food intake in normal and hypothalamic obese rats

Effects of alloxan induced diabetes on the feeding patterns of rats.

Absence of effect of intraaortal glucose infusions upon spontaneous meals of rats.

Mechanism of the Regulation of Food Intake

Beyond economics and nutrition; the complex basis of food policy.